Two-dimensional adaptive block Kalman filtering of SAR imagery

Includes bibliographical references.Speckle effects are commonly observed in synthetic aperture radar (SAR) imagery. In airborne SAR systems the effect of this degradation reduces the accuracy of detection substantially. Thus, the elimination of this noise is an important task in SAR imaging systems. In this paper a new method for speckle noise removal is introduced using 2-D adaptive block Kalman filtering (ABKF). The image process is represented by an autoregressive (AR) model with nonsymmetric half-plane (NSHP) region of support. New 2-D Kalman filtering equations are derived which take into account not only the effect of speckles as a multiplicative noise but also those of the additive receiver thermal noise and the blur. This method assumes local stationarity within a processing window, whereas the image can be assumed to be globally nonstationary. A recursive identification process using the stochastic Newton approach is also proposed which can be used on-line to estimate the filter parameters based upon the information within each new block of the image. Simulation results on several images are provided to indicate the effectiveness of the proposed method when used to remove the effects of speckle noise as well as that of the additive noise

Two-dimensional recursive parameter identification for adaptive Kalman filtering

Includes bibliographical references (page 1081).This paper is concerned with the development of a 2-D adaptive Kalman filtering by recursive adjustment of the parameters of an autoregressive (AR) image model with non symmetric half-plane (NSHP) region of support. The image and degradation models are formulated in a 2-D state-space model, for which the relevant 2-D Kalman filtering equations are given. The recursive parameter identification is achieved using the extension of the stochastic Newton approach to the 2-D case. This process can be implemented on-line to estimate the image model parameters based upon the local statistics in every processing window. Simulation results for removing an additive noise from a degraded image are also presented

Principal component extraction using recursive least squares learning

Includes bibliographical references.A new neural network-based approach is introduced for recursive computation of the principal components of a stationary vector stochastic process. The neurons of a single layer network are sequentially trained using a recursive least squares squares (RLS) type algorithm to extract the principal components of the input process. The optimality criterion is based on retaining the maximum information contained in the input sequence so as to be able to reconstruct the network inputs from the corresponding outputs with minimum mean squared error. The proof of the convergence of the weight vectors to the principal eigenvectors is also established. A simulation example is given to show the accuracy and speed advantages of this algorithm in comparison with the existing methods. Finally, the application of this learning algorithm to image data reduction and filtering of images degraded by additive and/or multiplicative noise is considered

When NLP meets SDN : an application to Global Internet eXchange Network

Software-Defined Networking (SDN) and its extension Intent-Based Networking (IBN) are network paradigms that enable dynamic, programmatically efficient network configuration. IBN allows network operators to express an outcome or business objective without the low-level configurations necessary to program the network to achieve these demands. Existing research proposals for IBN introduce several systems to translate users intents into network infrastructure configurations. Despite the positive aspects of these proposals, they still suffer from many drawbacks. Some require users to learn a new intent definition language. Some others may lack the appropriate grammar to make these frameworks recognize the intent correctly. In this paper, we introduce a framework leveraging the capabilities of Natural Language Processing (NLP) for network management from an operator utterances. In order to understand natural language, our framework uses the sequence-to-sequence (seq2seq) learning model based on recurrent neural networks (LSTM). The model has been improved by using word embedding and user feedback. As a proof of concept, we implement our framework for network management in a Global Internet eXchange Network and evaluate its practicality regarding NLP accuracy and network performance