neuralnetworks (NN) are now widely used and renown to solve recognition and classification problems. The present paper aims at showing how their learning capability can be applied to adaptive signal processing proble...
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ISBN:
(纸本)0780375033
neuralnetworks (NN) are now widely used and renown to solve recognition and classification problems. The present paper aims at showing how their learning capability can be applied to adaptive signal processing problems, either in replacement of conventional adaptive methods or to cope with most difficult cases raised by mobile space communication: non linear and/or non stationary problems. A brief overview of NN is given in the first section, highlighting their key features approximation capability, learning characteristic, etc.. The following sections focus on 3 majors applications to Space Communications: system and channel identification, equalization, and predistortion. The conclusion reached in this paper is that NN has no counterpart able to yield general solutions to these classes of problems with a single tool.
processing multichannel signals using digital signal processing techniques has received increased attention lately due to its importance in applications, such as multimedia technologies and telecommunications. The per...
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ISBN:
(纸本)0780358007
processing multichannel signals using digital signal processing techniques has received increased attention lately due to its importance in applications, such as multimedia technologies and telecommunications. The perspective of the topic offered here is one that comes primarily from work done in the field of multichannel imageprocessing. The adaptive filtering techniques discussed in the paper relate to imageprocessing with the emphasis placed primarily on filtering algorithms based on fuzzy logic concepts, multidimensional scaling, and order statistics-based designs. The strong potential of adaptive filters for multichannel imageprocessing is illustrated with several examples.
Extreme value theory is a branch of statistics that concerns the distribution of data of unusually low or high value, i.e. in the tails of some distribution. These extremal points are important in many applications as...
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Extreme value theory is a branch of statistics that concerns the distribution of data of unusually low or high value, i.e. in the tails of some distribution. These extremal points are important in many applications as they represent the outlying regions of normal events against which we may wish to define abnormal events. In the context of density modelling, novelty detection or radial-basis function systems, points that lie outside of the range of expected extreme values may be flagged as outliers. There has been interest in the area of novelty detection, but decisions as to whether a point is an outlier or not tend to be made on the basis of exceeding some (heuristic) threshold. It is shown that a more principled approach may be taken using extreme value statistics.
The application of task-specific knowledge to initialize the network weights prior to training is studied. Supervised neural network training is a high dimensional optimization problem and the initial conditions of th...
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The application of task-specific knowledge to initialize the network weights prior to training is studied. Supervised neural network training is a high dimensional optimization problem and the initial conditions of the search are critical to the quality of the solutions and the speed of the convergence to the solution. Rule insertion into fuzzy neuralnetworks can reduce the training time and lead to better solutions.
Artificial neuralnetworks present a powerful tool to analyze complex systems. They have been long used to tackle the difficulties of image analysis and interpretation with applications ranging from character recognit...
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Artificial neuralnetworks present a powerful tool to analyze complex systems. They have been long used to tackle the difficulties of image analysis and interpretation with applications ranging from character recognition to colour imageprocessing. This paper presents a novel approach which exploits the generality of expressions available in the area of Constructive Type Theory and its potential for the production of guaranteed bug free, probably correct software to develop a working neural Network Prototype. To illustrate the possible applications of our work we will present results from two examples arising from our co-operation with the Dover Harbour Board.
In the present work an adaptation of the Cellular neural Network (CNN) model to grey scale imageprocessing is proposed. This task is performed programming the network to work as a classical spatial filter, taking adv...
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ISBN:
(纸本)0852967217
In the present work an adaptation of the Cellular neural Network (CNN) model to grey scale imageprocessing is proposed. This task is performed programming the network to work as a classical spatial filter, taking advantage of the neural Network structure in order to improve the filtering effects. This enhancement is carried out by the inclusion of the feedback of the state variables and the adaptation of the input bias of every neuron based on the brightness of the image. A proper choice of the gain of the output function may also improve some of the network capabilities.
This paper discusses supervised and unsupervised neuralnetworks approaches to fetal echocardiographic image segmentation. The obtained results were compared with images segmented by a known unsupervised clustering te...
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This paper discusses supervised and unsupervised neuralnetworks approaches to fetal echocardiographic image segmentation. The obtained results were compared with images segmented by a known unsupervised clustering technique (i.e. k-means). The visual aspect of the segmented images was evaluated with respect to its visual quality by an expert. A subset of the segmented images showed sufficient details of the internal heart anatomy to allow medical diagnosis. The visual observation was matched closely by our unsupervised image segmentation approach, using the modified Hubert index.
neuralnetworks were used to solve invariant pattern classification problems. The first one consists of a pure neural solution. The neural network learns by itself the pre-processing required and extracts local inform...
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neuralnetworks were used to solve invariant pattern classification problems. The first one consists of a pure neural solution. The neural network learns by itself the pre-processing required and extracts local information. The second one consists of extracting invariant features by using analytical methods. A solution based on the second approach where two types of features are used in the step of information extraction is proposed. These features are fed to a neural network which is used for partitioning the space in regions corresponding to classes and consequently for realizing the classification step in a pattern recognition system independent of certain geometric transformations of the space.
A set of solutions are described with respect to the pre-processing, automatic acquisition, manipulation and interpretation of radar images based on advanced neuralnetworks, pattern recognition and other computationa...
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A set of solutions are described with respect to the pre-processing, automatic acquisition, manipulation and interpretation of radar images based on advanced neuralnetworks, pattern recognition and other computational intelligence techniques. The solutions have demonstrated the benefits of applying input dimension reduction techniques, Kahunen-Loeve transforms (PCA) and Walsh-Hadamard transforms (WH-PCS) methods on radar image recognition systems. Recognition results were considered satisfactory for the data sets tested.
Raman spectroscopy proves to be a versatile technique for forensic tasks. Whilst it is very easy and fast to record a spectrum, it may be very time-consuming for the non-experts (and even the experts) to identify chem...
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Raman spectroscopy proves to be a versatile technique for forensic tasks. Whilst it is very easy and fast to record a spectrum, it may be very time-consuming for the non-experts (and even the experts) to identify chemicals from the large database of Raman spectra of these materials. Parallel developments in the field of neuralnetworks have come to a stage that they can participate well in the recognition of these materials. In this paper, a novel neural network-based technique is developed and presented for the quick identification of chemical compounds, in particular narcotics and explosives. Preliminary results suggest this hybrid network has a great potential for forensic applications and for recognition of materials, in general.
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