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Piedras Negras, Mexico

Martin-Atienza B.,Autonomous University of Baja California | Alvarez-Borrego J.,Research Center Cientifica Educacion
International Geoscience and Remote Sensing Symposium (IGARSS) | Year: 2013

The sunlight reflection process in the sea surface, considering a two-dimensional geometric model with variable reflection angle, is examined and the corresponding equations are derived. A synthetic data surface is used to calculate the corresponding glitter pattern. An analysis of the relationship between the variance of the surface slopes and the variance of the intensity values in the glitter pattern are calculated considering a gaussian distribution and a non-gaussian distribution of the surface slopes. The results obtained for both distributions are compared and presented graphically. © 2013 IEEE.

Puente N.P.,Autonomous University of Baja California | Chaikina E.I.,Research Center Cientifica Educacion | Herath S.,Missouri University of Science and Technology | Yamilov A.,Missouri University of Science and Technology
Applied Optics | Year: 2011

We present results of experimental and theoretical studies of polarization-resolved light transmission through optical fiber with disorder generated in its germanium-doped core via UV radiation transmitted through a diffuser. In samples longer than a certain characteristic length, the power transmitted with preserved polarization is observed to be distributed over all forward-propagating modes, as evidenced by the Rayleigh negative exponential distribution of the near-field intensity at the output surface of the fiber. Furthermore, the transmitted power becomes also equally distributed over both polarizations. To describe the optical properties of the fibers with the experimentally induced disorder, a theoretical model based on coupled-mode theory is developed. The obtained analytical expression for the correlation function describing spatial properties of the disorder shows that it is highly anisotropic. Our calculations demonstrate that this experimentally controllable anisotropy can lead to suppression of the radiative leakage of the propagating modes, so that intermode coupling becomes the dominant scattering process. The obtained theoretical expressions for the polarization-resolved transmission fit very well with the experimental data, and the information extracted from the fit shows that radiative leakage is indeed small. The reported technique provides an easy way to fabricate different configurations of controlled disorder in optical fibers suitable for such applications as random fiber lasers. © 2011 Optical Society of America.

Birt T.P.,Queens University | Carter H.R.,California Institute of Environmental Studies | Whitworth D.L.,California Institute of Environmental Studies | McDonald A.,Queens University | And 6 more authors.
Auk | Year: 2012

Population genetic structure was characterized in Xantus's Murrelet (Synthliboramphus hypoleucus) by analyzing variation in the mitochondrial control region (505 samples) and 12 microsatellite loci (428 samples) in birds captured at all 13 current breeding areas in southern California and northwestern Baja California, Mexico. The two types of molecular markers were consistent in revealing strong genetic differentiation between the two currently recognized subspecies (S. h. hypoleucus and S. h. scrippsi) and little or no differentiation among breeding areas within subspecies. Estimates of gene flow were essentially zero, and no evidence for admixture was found. Gene flow among breeding locations within subspecies, on the other hand, was seemingly high. Given these genetic results, as well as clear morphological differences between the subspecies and the apparent lack of interbreeding at breeding areas where the two forms are sympatric, we suggest that two species be recognized. Both forms are genetically distinct from Craveri's Murrelet (S. craveri), a closely related species whose breeding range partially overlaps that of Xantus's Murrelet. Taxonomic subdivision of Xantus's Murrelet introduces new conservation concerns, especially for S. h. hypoleucus, which urgently requires greater study and protective efforts. © The American Ornithologists' Union, 2012.

Leyva J.A.L.,Research Center Cientifica Educacion | Mondragon A.A.,Research Center Cientifica Educacion | Garcia E.,Autonomous University of Baja California | Mendieta F.J.,Mexicana University | And 2 more authors.
Optical Engineering | Year: 2012

We describe a homodyne optical Costas loop receiver intended to detect weak coherent states with diffused phase and suppressed carrier phase modulation. In order to get the information contained in the quadrature components of the optical field, we implement an 8-port receiver operating at 1550 nm, based on the manipulation of the state of polarization of both the local oscillator and the data signal. Employing binary phase-shift keying, we make measurements in the time and frequency domain of the quantum noise and bit error rate using an optimum loop filter, and compare the performance of our receiver against the standard quantum limit for the simultaneous quadrature detection, considering both ideal conditions and the overall efficiency of our set up. © 2012 Society of Photo-Optical Instrumentation Engineers (SPIE).

Aguilar-Gonzalez P.M.,Research Center Cientifica Educacion | Kober V.,Research Center Cientifica Educacion
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2012

Correlation filters for object detection use information about the appearance and shape of the object of interest. Therefore, detection performance degrades when the appearance of the object in the scene differs from the appearance used in the filter design process. This problem has been approached by utilizing composite filters designed from a training set containing known views of the object of interest. However, common composite filter design is usually carried out under the assumption that the ideal appearance and shape of the target are known. In this work we propose an algorithm for composite filter design using noisy training images. The algorithm is a modification of the class synthetic discriminant function technique that uses arbitrary filter impulse responses. Furthermore, filters can be adapted to achieve a prescribed discrimination capability for a class of backgrounds if a representative sample is known. Computer simulation results obtained with the proposed algorithm are presented and compared with those of common composite correlation filters. © 2012 Springer-Verlag Berlin Heidelberg.

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