The problem of finding a subset of points in a pattern that best match to a subset of points in another pattern through a transformation in an optimal sense is considered. An exhaustive search to find the best assignm...
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The problem of finding a subset of points in a pattern that best match to a subset of points in another pattern through a transformation in an optimal sense is considered. An exhaustive search to find the best assignment mapping one set of points to another set is, if the number of points that are to be matched is large, computationally expensive. A genetic algorithm that searches for the best ('almost the best') assignment efficiently is described. To map the point pattern matching into the framework of a genetic algorithm, a fitness function that is inversely proportional to the match error and a scheme for encoding an assignment between two sets of points into a string are used, along with a genetic operator known as the mixed-type partial matching crossover. Experimental results have demonstrated the robustness and the fast convergence of the algorithm. The algorithm can be applied to n-dimensional point patterns and any transformation. Results are presented for two-dimensional point patterns and a similarity transformation.< >
A self-configurable satellite communication network that can be dynamically configured to different maps, to best meet the network requirements, by means of a modified Kohonen self-organization procedure is described....
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A self-configurable satellite communication network that can be dynamically configured to different maps, to best meet the network requirements, by means of a modified Kohonen self-organization procedure is described. The model consists of three stages. The first stage is the pattern recognition task, in which an exemplar map that best meets the current network requirements is selected. The second stage is an analysis of the discrepancy between the chosen exemplar map and the state of the network, and adaptively modifies the chosen exemplar map to conform closely to the network requirement (input data pattern) by Kohonen's self-organization procedure. On the basis of certain performance criteria, it is decided in the third stage whether a new map is generated to replace the original map. Experimental results are presented to demonstrate that the self-organization model can dynamically configure maps for a satellite communication network.< >
Real-time imageprocessing has been achieved by using an optical scanning system in conjunction with electronic hardware. A report of experimental results on edge extraction and image thresholding for transmissive obj...
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Real-time imageprocessing has been achieved by using an optical scanning system in conjunction with electronic hardware. A report of experimental results on edge extraction and image thresholding for transmissive objects is presented. Advantages and limitations of the techniques are identified. The results indicate that real-time edge extraction and image thresholding can be satisfactorily achieved.< >
A qualitative study is made of the image reconstruction capabilities of binary phase-only filters (BPOFs) and the binary Hartley phase-only filters (BHPOFs). It is found that the BPOF and BHPOF reconstruct edge-enhanc...
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A qualitative study is made of the image reconstruction capabilities of binary phase-only filters (BPOFs) and the binary Hartley phase-only filters (BHPOFs). It is found that the BPOF and BHPOF reconstruct edge-enhanced versions of the original object functions and that the image reconstruction of the BHPOF is better than that of the BPOF. However, for some applications such as optical interconnections, edge enhanced reconstruction is not desirable. Filled image reconstruction is achieved by using a Gaussian apodized mask on the BPOF and BHPOF. Also, a real-time hybrid optical system for such filled image reconstruction is presented.< >
In microwave radio communication networks, the transmission capacity can be doubled by using orthogonally polarized quadrature amplitude modulated (QAM) carriers. The orthogonally polarized waves can suffer degradatio...
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In microwave radio communication networks, the transmission capacity can be doubled by using orthogonally polarized quadrature amplitude modulated (QAM) carriers. The orthogonally polarized waves can suffer degradation due to carrier-to-cross-polarization interference (C/XPI). Particularly during multipath fading, such degradation would become intolerable. Different canceller structures are proposed to mitigate the effect of cross-polarization. Among these are the diagonalizer, the LMS, and the bootstrapped cancellers. The bootstrapped canceller has been implemented in different applications such as satellite dual-polarized communication, tactical communication, and QAM microwave radio. The probability of error performance of the bootstrapped cross-polarization canceller (BXPC) is studied and compared to the performance of other cancellers. The performance of the three cancellers is compared numerically for the 16 QAM with r=-10 dB, and -5 dB. It is shown that the LMS canceller outperforms the diagonalizers, particularly when the cross-coupling is high. Except for a very low signal-to-noise ratio, the BXPC outperforms the LMS with 64 QAM, more that with 16 QAM.< >
Two types of high-resolution direction-finding algorithms which use the fourth-order cumulants of the array data are derived. One is a MUSIC-like technique based on eigendecomposition of a suitably defined cumulant ma...
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Two types of high-resolution direction-finding algorithms which use the fourth-order cumulants of the array data are derived. One is a MUSIC-like technique based on eigendecomposition of a suitably defined cumulant matrix. The other is an optimal (asymptotically minimum variance) estimator based on minimization of a certain cost function.< >
Various techniques have been studied for the sampling of bandpass *** this paper,we present a comparative study of quadrature sampling and direct sampling of bandpass ***,both schemes provide efficient sampling of a b...
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Various techniques have been studied for the sampling of bandpass *** this paper,we present a comparative study of quadrature sampling and direct sampling of bandpass ***,both schemes provide efficient sampling of a bandpass signal at a minimum data rate and at the same time demultiplex the in-phase and quadrature components. In reality,imperfect circuit parameters lead to nonideal sampling, resulting in quadrature *** form relations for quadrature interference for quadrature sampling and direct sampling are derived and *** analysis shows that quadrature interference is inversely proportional to the variance of sampling phase jittering.
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