In the paper, for enhancing the security of the traditional LSB matching, two improved LSB-matching methods are proposed. In the steganograhical procedure, the Markov chain distance based on the second-order statistics is chosen as the security metric to control the modification directions of ±1 embedding. The first method is based on stochastic modification, which directly determines the modif...

AbstructThis paper presents two classes of adaptive blind algorithms based on secondand higher order statistics. The first class contains fast recursive algorithms whose cost functions involve second and thirdor fourth-order cumulants. These algorithms are stochastic gradient-based but have structures similar to the fast transversal filters (FTF) algorithms. The second class is composed of two ...

Cognitive radio is a new concept of reusing spectrum in an opportunistic manner. Cognitive radio is motivated by recent measurements of spectrum utilization, showing unused resources in frequency, time and space. Introducing cognitive radios in a primary network inevitably creates increased interference to the primary users. Secondary users must sense the spectrum and detect primary users’ sign...

We address the problem of Blind Source Separation (BSS) in the context of instantaneous (memoryless) linear mixtures, where the unknown mixing coefficients are time varying, changing periodically in time. Such a mixing model is realistic, e.g., when considering a biological or physiological system where the mixing coefficients are affected by periodic processes like breathing, heart-beating etc...

Explicit expressions for the second order statistics of cepstral components representing clean and noisy signal waveforms are derived. The noise is assumed additive to the signal, and the spectral components of each process are assumed statistically independent complex Gaussian random variables. The key result developed here is an explicit expression for the cross-covariance between the log-per...

This paper focuses on directional textures and proposes a new statistical approach for the second order description of an orientation vector field. We tackle two of the main high level properties that drive the perceptual grouping of texture: directionality and periodicity. Our method is based on the measure of similarity between two orientation vectors separated by a given displacement. We pro...

A second-order method for blind source separation of noisy instantaneous linear mixtures is presented and analyzed for the case where the signal order k and noise covariance GGH are unknown. Only a data set X of dimension n> k and of sample size m is observed, where X = AP + GW. The quality of separation depends on source-observation ratio }, the degree of spectral diversity, and the second-ord...

| an algebraic approach Ulf Lindgren Department of Applied Electronics Chalmers University of Technology S-412 96 G oteborg, Sweden [email protected] Alle-Jan van der Veen Department of Electrical Engineering Delft University of Technology 2628 CD Delft, The Netherlands [email protected] Two unknown non-white stochastic sources (e.g. speech signals) are dynamically mixed by an un...

Architecture–based techniques for reliability assessment of software applications have received increased attention in the past few years due to the advent of component–based software development paradigm. Most of the prior research efforts in architecture–based analysis use the composite solution approach to solve the architecture–based models in order to estimate application reliability. Thou...