Search results for "COD"
showing 10 items of 2985 documents
The influence of severity of fading on the statistical properties of the capacity of Nakagami-m channels with MRC and EGC
2010
In this article, we have studied the statistical properties of the capacity of Nakagami-m channels when spatial diversity combining, such as maximal ratio combining (MRC) and equal gain combining (EGC), is employed at the receiver. The presented results provide insight into the statistical properties of the channel capacity under a wide range of fading conditions in wireless links using L-branch diversity combining techniques. We have derived closed-form analytical expressions for the probability density function (PDF), cumulative distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the channel capacity. The statistical properties of the capacity ar…
Filter multiplexing by use of spatial Code Division Multiple Access approach.
2003
The increasing popularity of optical communication has also brought a demand for a broader bandwidth. The trend, naturally, was to implement methods from traditional electronic communication. One of the most effective traditional methods is Code Division Multiple Access. In this research, we suggest the use of this approach for spatial coding applied to images. The approach is to multiplex several filters into one plane while keeping their mutual orthogonality. It is shown that if the filters are limited by their bandwidth, the output of all the filters can be sampled in the original image resolution and fully recovered through an all-optical setup. The theoretical analysis of such a setup …
Single-channel polychromatic pattern recognition by the use of a joint-transform correlator.
2010
We present a single-channel system for color image recognition that is based on a joint-transform correlator setup. The color images are encoded as phase and amplitude functions, inspired from the Munsell color representation. A real-time implementation of the new codification method can be achieved by the use of a spatial light modulator operating in phase-only modulation mode. We determine the optimal codification for a linear color-phase code. Its performance is compared with a conventional multichannel correlator by means of computer simulations. Experimental results are also presented.
Super Resolution Methods Implementing Diffractive Masks Having a Certain Degree of Periodicity
2011
This section presents an approach that provides super resolved imaging at the center of the field of view and yet allows to see the remaining of the original field of view with original resolution. This operation resembles optical zooming while the zoomed and the nonzoomed images are obtained simultaneously. This is obtained by taking a single snap-shot and using a single imaging lens. The technique utilizes a special static/still coding element and a postprocessing algorithmic, without any mechanical movements.
Allium kyrenium (Amaryllidaceae), a new species from Northern Cyprus.
2015
Allium kyrenium, a new species of Allium sect. Codonoprasum, is described and illustrated from northern Cyprus. It is a very circumscribed geophyte growing on the calcareous cliffs of the Kyrenia range. This diploid species, with a somatic chromosome number 2n = 16, shows close morphological relationships with A. stamineum, a species complex distributed in the eastern Mediterranean area. Its morphology, karyology, leaf anatomy, ecology, conservation status and taxonomical relationships with the allied species belonging to the A. stamineum group are examined.
Characterizing a hybrid zone between a cryptic species pair of freshwater snails.
2015
Characterizing hybrid zones and their dynamics is a central goal in evolutionary biology, but this is particularly challenging for morphologically cryptic species. The lack of conspicuous divergence between parental types means intermediate hybrid forms often go undetected. We aimed to detect and characterize a suspected hybrid zone between a pair of morphologically cryptic lineages of the freshwater snail, Radix. We sampled Radix from across a contact zone between two mitochondrial lineages (Radix balthica and an undescribed lineage termed 'MOTU3') and detected admixture between two nuclear genotype clusters, which were significantly but not categorically associated with the mitochondrial …
Morphological vs. molecular delineation of taxa across montane regions in Europe: the case study of Gammarus balcanicus Schäferna, (Crustacea: Amphip…
2014
Mountainous areas are characterized by substantial biodiversity and endemicity due to their complex geological history and habitat fragmentation. Hence, it can be assumed that particularly high species richness can be found in organisms with limited dispersal capabilities that inhabit mountain streams. A number of scientific papers focus on molecular phylogeography or traditional taxonomy of species or species groups inhabiting such habitats. However, there is a lack of studies that integrate morphological and molecular data to identify and delineate cryptic species. For practical reasons, uncovering cryptic diversity is crucial in taxa used in biomonitoring. Distinct species, hard to separ…
The parasitoid species complex associated with sexual and parthenogenetic Naryciinae (Lepidoptera: Psychidae): Integrating ecological and molecular a…
2011
This study describes the parasitoid species complex associated with seven closely related species of sexual (Siederia rupi- collella, S. listerella, Dahlica lazuri, D. charlottae and D. lichenella) and parthenogenetic (Dahlica fennicella and D. triquetrella) Naryciinae (Lepidoptera: Psychidae) in Central Finland. A thorough ecological analysis of all the species of parasitoids recorded was combined with analyses of molecular data. Mitochondrial and nuclear DNA data were obtained from all the species in order to (1) detect cryptic species associated with host specialization, (2) assign undescribed males to females, and (3) verify the morphological identification of closely related species. A…
Design of a real-time spectroscopic rotating compensator ellipsometer without systematic errors
2014
6th International Conference on Spectroscopic Ellipsometry (ICSE), Kyoto, JAPAN, MAY 26-31, 2013; International audience; We describe a spectroscopic ellipsometer in the visible domain (400-800 nm) based on a rotating compensator technology using two detectors. The classical analyzer is replaced by a fixed Rochon birefringent beamsplitter which splits the incidence light wave into two perpendicularly polarized waves, one oriented at +45 degrees and the other one at-45 degrees according to the plane of incidence. Both emergent optical signals are analyzed by two identical CCD detectors which are synchronized by an optical encoder fixed on the shaft of the step-by-step motor of the compensato…
Reducing complexity in H.264/AVC motion estimation by using a GPU
2011
H.264/AVC applies a complex mode decision technique that has high computational complexity in order to reduce the temporal redundancies of video sequences. Several algorithms have been proposed in the literature in recent years with the aim of accelerating this part of the encoding process. Recently, with the emergence of many-core processors or accelerators, a new approach can be adopted for reducing the complexity of the H.264/AVC encoding algorithm. This paper focuses on reducing the inter prediction complexity adopted in H.264/AVC and proposes a GPU-based implementation using CUDA. Experimental results show that the proposed approach reduces the complexity by as much as 99% (100x of spe…