on the solvability of periodic boundary value problems with impulse in this work we obtain some new results concerning the existence of solutions to an impulsive first order nonlinear ordinary differential equation with periodic boundary conditions the ideas involve differential inequalities and schaefer s fixed point theorem

second order initial value problems with non absolute integrals in ordered banach spaces abstract in this paper we derive the existence and comparison results for second order initial value problems in ordered banach spaces the considered problems can be implicit singular functional discontinuous and nonlocal the main tools are fixed point results in ordered spaces and the theory of locally hl integrable vector valued functions

existence results for urysohn integral inclusions involving the henstock integral this paper presents two existence results for urysohn integral inclusions in banach spaces the set valued integral involved being the henstock integral in particular the existence of continuous solutions for integral inclusions of volterra and of hammerstein type is obtained our results extend the existence theorems given in literature in the single or set valued case under bochner or pettis integrability hypothesis the compactness of solutions set is also studied

positive solutions of periodic boundary value problems for nonlinear first order impulsive differential equations abstract motivated by liu y liu further results on periodic boundary value problems for nonlinear first order impulsive functional differential equations j math anal appl 327 2007 435 452 li et al x li x lin d jiang x zhang existence and multiplicity of positive periodic solutions to functional differential equations with impulse effects nonlinear anal 62 2005 683 701 and liu and ge y liu w ge stability theorems and existence results for periodic solutions of nonlinear impulsive delay differential equations with variable coefficients nonlinear anal 57 2004 363 399 this paper is concerned with the periodic boundary value problem pbvp for short for the nonlinear impulsive differential equation x t a t x t f t x t a e t 0 t t 1 t p x t k x t k x t k i k x t k k 1 p x t x 0 we obtain new sufficient conditions for the existence of at least one two or three positive solutions of the above pbvp respectively examples are presented to illustrate the main results

stability and euler approximation of one sided lipschitz differential inclusions ordinary differential and functional differential inclusions with compact right hand sides are considered stability theorems of filippov s type in the convex and nonconvex case are proved under a one sided lipschitz condition which extends the notions of lipschitz continuity dissipativity and the uniform one sided lipschitz condition for set valued mappings the accuracy of approximation of the solution sets by means of the euler discretization scheme for both types of inclusions is estimated

variational methods to the second order impulsive differential equation with dirichlet boundary value problem in this paper we study the existence of solutions for a class of second order impulsive differential equation by using the critical point theorem of y jabri and an even functional theorem we give some new criteria to guarantee that the impulsive differential equation has at least one solution infinitely many solutions under the assumption that a nonlinear term satisfies sublinear superlinear asymptotically linear respectively some recent results are extended and conditions of assumptions are simplified finally some examples are presented to illustrate our main results

solutions of cauchy and periodic problems for evolution inclusions with multi valued wλ0 pseudomonotone maps abstract we consider differential operator inclusions with w 0 pseudomonotone multi valued maps the problem of investigation of solutions of cauchy and periodic problems is solved by faedo galerkin fg method important a priori estimates are obtained some topological descriptions of the resolvent operators are made

gauge integrals and selections of weakly compact valued multifunctions abstract in the paper henstock mcshane birkhoff and variationally multivalued integrals are studied for multifunctions taking values in the hyperspace of convex and weakly compact subsets of a general banach space x in particular the existence of selections integrable in the same sense of the corresponding multifunctions has been considered

infinitely many solutions for a class of nonlinear impulsive differential equations with periodic boundary conditions in this paper we consider the existence of solutions for a class of nonlinear impulsive problems with periodic boundary conditions by using critical point theory we obtain some existence theorems of infinitely many solutions for the nonlinear impulsive problem when the impulsive functions are superlinear we extend and improve some recent results

robust optimum detection of transform domain multiplicative watermarks digital watermarking is an emerging technique to protect data security and intellectual property right identification or verification of watermarking patterns can be achieved by detecting watermarks in received signals however one of the biggest challenges in watermarking detection is that the strengths of the watermark signals will change after being distorted by an attacker in a watermarking channel meanwhile the embedding strengths may be adapted to the original signals which are unknown at the receiver end further the original signals are often highly non gaussian although some work has been done on optimum detection of watermarks the uncertainty of watermark signal strengths and real statistical behavior of multimedia contents have not been taken into account simultaneously much more study is needed to enhance the performance of watermarking systems since multiplicative watermarks are robust and well suited for copyright protection this paper presents our investigation on robust optimum detection of multiplicative watermarks for sub band transformed domains such as the discrete cosine transform dct discrete wavelet transform dwt and pyramid transform a class of generalized correlators is constructed based on the generalized gaussian distributions thresholding methods to achieve a given false alarm rate and the performance analyses are provided the square root detector is designed and demonstrated to have near optimal performance for a large set of natural images and can be employed as a universally optimal detector or decoder for images and video the locally most powerful detection method is then extended to dft domain multiplicative watermarking with the magnitudes of coefficients modeled by the weibull distributions another class of detectors is built based on this statistical modeling the robust optimum detection of multiplicative watermarks can be applied to copyright notification enforcement and broadcast monitoring we have applied the robust optimum watermarking detection to combined audio and video watermarking

a new decoder for the optimum recovery of nonadditive watermarks watermark detection i e the detection of an invisible signal hidden within an image for copyright protection or data authentication has classically been tackled by means of correlation based techniques nevertheless when watermark embedding does not obey an additive rule or when the features the watermark is superimposed on do not follow a gaussian pdf correlation based decoding is not the optimum choice a new decoding algorithm is presented here which is optimum for nonadditive watermarks embedded in the magnitude of a set of full frame dft coefficients of the host image by relying on statistical decision theory the structure of the optimum is derived according to the neyman pearson criterion thus permitting to minimize the missed detection probability subject to a given false detection rate the validity of the optimum decoder has been tested thoroughly to assess the improvement it permits to achieve from a robustness perspective the results we obtained confirm the superiority of the novel algorithm with respect to classical correlation based decoding

periodic boundary value problem for first order impulsive functional differential equations this paper discusses the periodic boundary value problem for a class of first order impulsive functional differential equations we establish several existence results under weaker hypotheses by using the leray schauder alternative the lower and upper solution method and the monotone iterative technique the corresponding results in the literature are improved or extended some examples are also given to illustrate the advantage of the results

optimal signature design for spread spectrum steganography for any given host image or group of host images and any block transform domain of interest we find the signature vector that when used for spread spectrum ss message embedding maximizes the signal to interference plus noise ratio sinr at the output of the corresponding maximum sinr linear filter we establish that under a colored gaussian assumption on the transform domain host data the same derived signature minimizes host distortion for any target message recovery error rate and maximizes the shannon capacity of the covert steganographic link then we derive jointly optimal signature and linear processor designs for ss embedding in linearly modified transform domain host data and demonstrate orders of magnitude improvement over current ss steganographic practices optimized multisignature multimessage embedding in the same host data is studied as well

variational methods to sturm liouville boundary value problem for impulsive differential equations abstract in this paper we study a linear sturm liouville impulsive problem and a nonlinear sturm liouville impulsive problem by applying a new approach via critical point theory and variational methods the existence results of positive solutions are obtained

on the existence of periodic solutions for differential inclusions in this paper we study the existence of periodic solutions for differential inclusions we prove existence theorems under various sets of hypotheses for both the nonconvex and convex problems also we show the existence of extreme solutions some feedback control systems are also considered

a new statistical detector for dwt based additive image watermarking using the gauss hermite expansion traditional statistical detectors of the discrete wavelet transform dwt based image watermarking use probability density functions pdfs that show inadequate matching with the empirical pdf of image coefficients in view o f the fact that they use a fixed number of parameters hence the decision values obtained from the estimated thresholds of these detectors provide substandard detection performance in this paper a new detector is proposed for the dwt based additive image watermarking wherein a pdf based on the gauss hermite expansion is used in view of the fact that this pdf provides a better statistical match to the empirical pdf by utilizing an appropriate number of parameters estimated from higher order moments of the image coefficients the decision threshold and the receiver operating characteristics are derived for the proposed detector experimental results on test images demonstrate that the proposed watermark detector performs better than other standard detectors such as the gaussian and generalized gaussian gg in terms of the probabilities of detection and false alarm as well as the efficacy it is also shown that detection performance of the proposed detector is more robust than the competitive gg detector in the case of compression additive white gaussian noise filtering or geometric attack

existence theorems of global solutions for nonlinear volterra type integral equations in banach spaces in this paper first a new fixed point theorem is established and then by the use of it the existence theorems of global solutions for nonlinear volterra type integral equations in banach spaces are investigated the results obtained in this paper generalize and improve the results corresponding to those obtained by others

a constructive approach towards the method of solution regions abstract in this work we develop the theory of solution regions with a constructive approach we also extend the theory to the case of general linear conditions and provide various sets of sufficient hypotheses for existence and multiplicity results

asymptotically optimal detection for additive watermarking in the dct and dwt domains most of the watermarking schemes that have been proposed until now employ a correlation detector matched filter the current paper proposes a new detector scheme that can be applied in the case of additive watermarking in the dct discrete cosine transform or dwt discrete wavelet transform domain certain properties of the probability density function of the coefficients in these domains are exploited thus an asymptotically optimal detector is constructed based on well known results of the detection theory experimental results prove the superiority of the proposed detector over the correlation detector

periodic n dimensional first order coupled systems and periodic schizophrenia phenomena abstract this paper introduces some existence and location results for periodic solutions of first order coupled nonlinear systems of n ordinary differential equations the arguments used are based on the arzela ascoli theorem and schauder s fixed point theorem combined with the upper and lower solution technique to illustrate the applicability of these problems an application to a mathematical model of the thyroid pituitary interaction and their homeostatic mechanism is included for specific cases of periodic events such as relapsing catatonia

initial value problems for nonlinear second order impulsive integro differential equations in banach spaces in this paper the fixed point theory is used to investigate the existence and uniqueness of solutions of initial value problems for nonlinear second order impulsive integro differential equations in banach spaces

periodic solutions for a class of differential inclusions in general banach spaces abstract let x be a real banach space a d a x x an m accretive operator and f r d a x a multi function which is 2 periodic with respect to its first argument has nonempty closed convex and weakly compact values and is strongly weakly upper semicontinuous in this paper we prove the existence of at least one solution for the problem u t a u t f t f t f t u t u t u t 2 in the case in which f satisfies an appropriate sign condition

periodic boundary value problems for first order impulsive dynamic equations on time scales this paper deals with the periodic boundary value problem for a class of first order impulsive dynamic equations on time scales we introduce a new notion of lower and upper solutions which extends the classical lower and upper solutions the existence of extremal solutions is presented by virtue of the method of lower and upper solutions coupled with monotone iterative technique an example is also included to illustrate the main results

almost periodic solutions for abstract impulsive differential equations this paper studies the existence and uniqueness of exponentially stable almost periodic solutions for abstract impulsive differential equations in banach space the investigations are carried out by means of the fractional powers of operators we construct an example to illustrate the feasibility of our results

systems of first order differential inclusions with maximal monotone terms in this paper we establish the existence of solutions to systems of first order differential inclusions with maximal monotone terms satisfying the periodic boundary condition our proofs rely on the theory of maximal monotone operators and the schauder and the kakutani fixed point theorems a notion of solution tube to these problems is introduced this notion generalizes the notion of upper and lower solutions of first order differential equations

convergence theorems for hl integrable vector valued functions with applications abstract in this paper we prove dominated and monotone convergence theorems for hl integrable banach valued functions these results and a fixed point theorem in ordered spaces are then applied to prove existence and comparison results for integral equations of fredholm type in ordered banach spaces involving kurzweil integrals or improper integrals results are used also to solve concrete second order functional boundary value problems involving discontinuities and singularities

solution tube method for impulsive periodic differential inclusions of first order abstract the aim of this paper is to obtain an existence result for impulsive differential inclusions of first order with boundary conditions in hilbert spaces under a hypothesis of integrability in the henstock lebesgue sense for the multifunction on the right hand side the proof is based on the assumption that there exists a solution tube for the inclusion taken under consideration this novel concept which generalizes the extensively used notions of upper and lower solution was adapted to the present setting finally a compactness property is proved

on the existence of solutions for nonlinear first order implicit impulsive integro differential equations abstract by using the monch fixed point theorem the purpose of this paper is to obtain the new existence theorems of solutions for a new class of initial value problems of nonlinear first order implicit impulsive integro differential equations in banach spaces under some weaker conditions

on the global bifurcation of periodic solutions of differential inclusions in hilbert spaces abstract in this paper applying the method of guiding functions we study the global bifurcation problems for periodic solutions of first order parametrized differential inclusions in hilbert spaces as application we consider the global structure of a set of periodic trajectories for a family of feedback control systems

convexity of the cost functional in an optimal control problem for a class of positive switched systems abstract this paper deals with the optimal control of a class of positive switched systems the main feature of this class is that switching alters only the diagonal entries of the dynamic matrix the control input is represented by the switching signal itself and the optimal control problem is that of minimizing a positive linear combination of the final state variable first the switched system is embedded in the class of bilinear systems with control variables living in a simplex for each time point the main result is that the cost is convex with respect to the control variables this ensures that any pontryagin solution is optimal algorithms to find the optimal solution are then presented and an example taken from a simplified model for hiv mutation mitigation is discussed

a study of multiplicative watermark detection in the contourlet domain using alpha stable distributions in the past decade several schemes for digital image watermarking have been proposed to protect the copyright of an image document or to provide proof of ownership in some identifiable fashion this paper proposes a novel multiplicative watermarking scheme in the contourlet domain the effectiveness of a watermark detector depends highly on the modeling of the transform domain coefficients in view of this we first investigate the modeling of the contourlet coefficients by the alpha stable distributions it is shown that the univariate alpha stable distribution fits the empirical data more accurately than the formerly used distributions such as the generalized gaussian and laplacian do we also show that the bivariate alpha stable distribution can capture the across scale dependencies of the contourlet coefficients motivated by the modeling results a blind watermark detector in the contourlet domain is designed by using the univariate and bivariate alpha stable distributions it is shown that the detectors based on both of these distributions provide higher detection rates than that based on the generalized gaussian distribution does however a watermark detector designed based on the alpha stable distribution with a value of its parameter other than 1 or 2 is computationally expensive because of the lack of a closed form expression for the distribution in this case therefore a watermark detector is designed based on the bivariate cauchy member of the alpha stable family for which 1 the resulting design yields a significantly reduced complexity detector and provides a performance that is much superior to that of the gg detector and very close to that of the detector corresponding to the best fit alpha stable distribution the robustness of the proposed bivariate cauchy detector against various kinds of attacks such as noise filtering and compression is studied and shown to be superior to that of the generalized gaussian detector

monotone method for a system of nonlinear mixed type implicit impulsive integro differential equations in banach spaces in this paper by using a monotone iterative technique in the presence of lower and upper solutions we discuss the existence of solutions for a new system of nonlinear mixed type implicit impulsive integro differential equations in banach spaces under wide monotonicity conditions and the noncompactness measure conditions we also obtain the existence of extremal solutions and a unique solution between lower and upper solutions

existence of positive periodic solutions for a neutral population model with delays and impulse in this paper by using the theory of abstract continuous theorem of k set contractive operator and some analysis techniques we obtain some sufficient conditions for the existence of positive periodic solutions for a neutral population model with delays and impulse

boundary value problems for a class of impulsive functional equations this paper is related to the existence and approximation of solutions for impulsive functional differential equations with periodic boundary conditions we study the existence and approximation of extremal solutions to different types of functional differential equations with impulses at fixed times by the use of the monotone method some of the options included in this formulation are differential equations with maximum and integro differential equations in this paper we also prove that the lipschitzian character of the function which introduces the functional dependence in a differential equation is not a necessary condition for the development of the monotone iterative technique to obtain a solution and to approximate the extremal solutions to the equation in a given functional interval the corresponding results are established for the impulsive case the general formulation includes several types of functional dependence delay equations equations with maxima integro differential equations finally we consider the case of functional dependence which is given by nonincreasing and bounded functions

existence and nonexistence results of impulsive first order problem with integral boundary condition abstract this paper is concerned with a first order impulsive boundary value problem ibvp for short with integral boundary condition and depending on a parameter we obtain the existence and nonexistence results of positive solutions for the ibvp when the nonlinear term and the impulses satisfy different requirements of superlinearity and sublinearity and the parameter lies in some intervals

extreme continuous selectors of multivalued maps and their applications abstract a theorem on the existence of continuous selectors whose values are extreme points is proved for a class of multivalued maps the theorem is used to study existence and properties of solutions to differential inclusions in banach spaces

optimal control of switching systems this paper considers an optimal control problem for a switching system for solving this problem we do not make any assumptions about the number of switches nor about the mode sequence they are determined by the solution of the problem the switching system is embedded into a larger family of systems and the optimization problem is formulated for the latter it is shown that the set of trajectories of the switching system is dense in the set of trajectories of the embedded system the relationship between the two sets of trajectories 1 motivates the shift of focus from the original problem to the more general one and 2 underlies the engineering relevance of the study of the second problem sufficient and necessary conditions for optimality are formulated for the second optimization problem if they exist bang bang type solutions of the embedded optimal control problem are solutions of the original problem otherwise suboptimal solutions are obtained via the chattering lemma

impulsive retarded differential equations in banach spaces via bochner lebesgue and henstock integrals t f t xt xt0 1 1 where is a given continuous function from r 0 r 0 to a banach space x and f is a continuous map from an open set r c r 0 x to x given a continuous function x t0 r t0 a x a 0 t0 r we follow 11 to deane xt r 0 x by xt x t r 0 t t0 t0 a the initial value problem 1 1 is equivalent to the integral equation

design and statistical analysis of a hash aided image watermarking system this paper develops a joint hashing watermarking scheme in which a short hash of the host signal is available to a detector potential applications include content tracking on public networks and forensic identification the host data into which the watermark is embedded are selected from a secret subset of the full frame discrete cosine transform of an image and the watermark is inserted through multiplicative embedding the hash is a binary version of selected original image coefficients we propose a maximum likelihood watermark detector based on a statistical image model the availability of a hash as side information to the detector modifies the posterior distribution of the marked coefficients we derive chernoff bounds on the receiver operating characteristic performance of the detector we show that host signal interference can be rejected if the hash function is suitably designed the relative difficulty of an eavesdropper s detection problem is also determined the eavesdropper does not know the secret key used monte carlo simulations are performed using photographic test images finally various attacks on the watermarked image are introduced to study the robustness of the derived detectors the joint hashing watermarking scheme outperforms the traditional hashless watermarking technique

asymptotically optimum universal watermark embedding and detection in the high snr regime the problem of optimum watermark embedding and detection was addressed in a recent paper by merhav and sabbag where the optimality criterion was the maximum false negative error exponent subject to a guaranteed false positive error exponent in particular merhav and sabbag derived universal asymptotically optimum embedding and detection rules under the assumption that the detector relies solely on second order joint empirical statistics of the received signal and the watermark in the case of a gaussian host signal and a gaussian attack however closed form expressions for the optimum embedding strategy and the false negative error exponent were not obtained in that work in this paper we derive the false negative error exponent for any given embedding strategy and use such a result to show that in general the optimum embedding rule depends on the variance of the host sequence and the variance of the attack noise we then focus on high signal to noise ratio snr regime deriving the optimum embedding strategy for such a setup in this case a universally optimum embedding rule turns out to exist and to be very simple with an intuitively appealing geometrical interpretation the effectiveness of the newly proposed embedding strategy is evaluated numerically

existence of solutions for first order pbvps with impulses on time scales in this paper we consider some kind of nonlinear periodic differential equation with impulses on time scales and give some new criteria for the existence of at least one solution by using differential inequalities and fixed point theorems

multiple solutions of impulsive sturm liouville boundary value problem via lower and upper solutions and variational methods abstract in this paper we prove the existence of multiple solutions for second order sturm liouville boundary value problem l u f x u x 0 1 r 1 u 0 r 2 u 0 where l u p x u q x u is a sturm liouville operator r 1 u u 0 u 0 r 2 u u 1 u 1 the technical approach is fully based on lower and upper solutions and variational methods the interesting point is that the existence of four solutions and seven solutions is given

study of singular boundary value problems for second order impulsive differential equations this paper studies the existence of extremal solutions for a class of singular boundary value problems of second order impulsive differential equations by using the method of upper and lower solutions and the monotone iterative technique criteria of the existence of extremal solutions are established

positive solutions for nonlinear first order periodic boundary value problems of impulsive dynamic equations on time scales in this paper existence criteria of positive solutions to a class of nonlinear first order periodic boundary value problems of impulsive dynamic equations on time scales are obtained the main tool used in this paper is the well known guo krasnoselskii fixed point theorem

a new proof of a theorem on optimal control of switched systems abstract recently sorin c bengea and raymond a decarlo sorin c bengea raymond a decarlo optimal control of switching systems automatica j ifac 41 2005 11 27 have offered a key result that the set of trajectories of the two switched system is dense in the set of trajectories of the embedded system this result was proven by means of relaxed controls and the chattering lemma in this paper we use the lyapunov theorem to give a new simple proof

existence for impulsive neutral integrodifferential inclusions with nonlocal initial conditions via fractional operators abstract this paper is mainly concerned with existence of mild solutions for a first order impulsive neutral integrodifferential inclusions with nonlocal initial conditions in norm we assume that the linear part generates an analytic semigroup and transform it into an integral inclusion by using a fixed point theorem for multi valued maps due to dhage a main existence theorem is established finally we present an example to illustrate this main theorem

impulsive anti periodic boundary value problem of first order integro differential equations this paper is concerned with the anti periodic boundary value problem of first order nonlinear impulsive integro differential equations we first establish a new comparison principle and then obtain the existence of extremal solutions by upper lower solution and monotone iterative techniques some examples are presented to illustrate the main results

on periodic solutions of multivalued nonlinear evolution equations in this paper first we prove a new existence theorem for periodic solutions of finite dimensional differential inclusions then we use this result and galerkin approximations to establish the existence of periodic trajectories for a class of nonlinear evolution inclusions an example of a parabolic nonlinear feedback control system is also worked out in detail

optimum decoding and detection of multiplicative watermarks this work addresses the problem of optimum decoding and detection of a multibit multiplicative watermark hosted by weibull distributed features a situation which is classically encountered for image watermarking in the magnitude of dft domain as such this work can be seen as an extension of the system described in a previous paper where the same problem is addressed for the case of 1 bit watermarking the theoretical analysis is validated through monte carlo simulations although the structure of the optimum decoder detector is derived in the absence of attacks some experimental results are also presented giving a measure of the overall robustness of the watermark when attacks are present

a new result on impulsive differential equations involving non absolutely convergent integrals in this paper we obtain as an application of a darbo type theorem global solutions for differential equations with impulse effects under the assumption that the function on the right hand side is integrable in the henstock sense we thus generalize several previously given results in literature for ordinary or impulsive equations

existence of solutions to first order impulsive periodic boundary value problems abstract this paper is concerned with the solvability of periodic boundary value problems for first order impulsive ordinary differential equations by using schaeffer s theorem a sufficient condition for existence of solution of the problem is obtained which extends and improves some known results in the literature

impulsive nonlocal differential equations through differential equations on time scales abstract we propose a non standard approach to impulsive differential equations in banach spaces by embedding this type of problems into differential dynamic problems on time scales we give an existence result for dynamic equations and as a consequence we obtain an existence result for impulsive differential equations

a logarithmic quantization index modulation for perceptually better data hiding in this paper a novel arrangement for quantizer levels in the quantization index modulation qim method is proposed due to perceptual advantages of logarithmic quantization and in order to solve the problems of a previous logarithmic quantization based method we used the compression function of law standard for quantization in this regard the host signal is first transformed into the logarithmic domain using the law compression function then the transformed data is quantized uniformly and the result is transformed back to the original domain using the inverse function the scalar method is then extended to vector quantization for this the magnitude of each host vector is quantized on the surface of hyperspheres which follow logarithmic radii optimum parameter for both scalar and vector cases is calculated according to the host signal distribution moreover inclusion of a secret key in the proposed method similar to the dither modulation in qim is introduced performance of the proposed method in both cases is analyzed and the analytical derivations are verified through extensive simulations on artificial signals the method is also simulated on real images and its performance is compared with previous scalar and vector quantization based methods results show that this method features stronger a watermark in comparison with conventional qim and as a result has better performance while it does not suffer from the drawbacks of a previously proposed logarithmic quantization algorithm

perceptual image hashing based on virtual watermark detection this paper proposes a new robust and secure perceptual image hashing technique based on virtual watermark detection the idea is justified by the fact that the watermark detector responds similarly to perceptually close images using a non embedded watermark the hash values are extracted in binary form with a perfect control over the probability distribution of the hash bits moreover a key is used to generate pseudo random noise whose real values contribute to the randomness of the feature vector with a significantly increased uncertainty of the adversary measured by mutual information in comparison with linear correlation experimentally the proposed technique has been shown to outperform related state of the art techniques recently proposed in the literature in terms of robustness with respect to image processing manipulations and geometric attacks

exponential stability of nonlinear impulsive neutral differential equations with delays abstract in this article a nonlinear impulsive neutral differential equation with time varying delays is considered by establishing a singular impulsive delay differential inequality and transforming the n dimensional impulsive neutral delay differential equation to a 2 n dimensional singular impulsive delay differential equation some sufficient conditions ensuring the global exponential stability in pc 1 of the zero solution of an impulsive neutral differential equation are obtained the results extend and improve on earlier publications an example is given to illustrate the theory

adaptive multiwavelet based watermarking through jpw masking in this paper a multibit multiplicative spread spectrum watermarking using the discrete multiwavelet including unbalanced and balanced multiwavelet transform is presented performance improvement with respect to existing algorithm is obtained by means of a new just perceptual weighting jpw model the new model incorporates various masking effects of human visual perception by taking into account the eye s sensitivity to noise changes depending on spatial frequency luminance and texture of all the image subbands in contrast to conventional jnd threshold model jpw describing minimum perceptual sensitivity weighting to noise changes is fitter for nonadditive watermarking specifically watermarking strength is adaptively adjusted to obtain minimum perceptual distortion by employing the jpw model correspondingly an adaptive optimum decoding is derived using a statistic model based on generalized gaussian distribution ggd for multiwavelet coefficients of the cover image furthermore the impact of multiwavelet characteristics on proposed watermarking scheme is also analyzed finally the experimental results show that proposed jpw model can improve the quality of the watermarked image and give more robustness of the watermark as compared with a variety of state of the art algorithms

locally optimum nonlinearities for dct watermark detection the issue of copyright protection of digital multimedia data has attracted a lot of attention during the last decade an efficient copyright protection method that has been gaining popularity is watermarking i e the embedding of a signature in a digital document that can be detected only by its rightful owner watermarks are usually blindly detected using correlating structures which would be optimal in the case of gaussian data however in the case of dct domain image watermarking the data is more heavy tailed and the correlator is clearly suboptimal nonlinear receivers have been shown to be particularly well suited for the detection of weak signals in heavy tailed noise as they are locally optimal this motivates the use of the gaussian tailed zero memory nonlinearity as well as the locally optimal cauchy nonlinearity for the detection of watermarks in dct transformed images we analyze the performance of these schemes theoretically and compare it to that of the traditionally used gaussian correlator but also to the recently proposed generalized gaussian detector which outperforms the correlator the theoretical analysis and the actual performance of these systems is assessed through experiments which verify the theoretical analysis and also justify the use of nonlinear structures for watermark detection the performance of the correlator and the nonlinear detectors in the presence of quantization is also analyzed using results from dither theory and also verified experimentally

periodic solutions of a neutral impulsive predator prey model with beddington deangelis functional response with delays in this paper we consider a neutral predator prey model with the beddington deangelis functional response and impulsive effect sufficient conditions are obtained for the existence of positive periodic solutions by a systematic qualitative analysis some known results in the literature are generalized

on the solution of dydx ap f x y abstract we prove a substantial extension of picard s theorem on the solvability of the ordinary differential equation dy dx f x y and also obtain a generalization of the result in terms of approximate derivative dy dx ap the results are illustrated by suitable examples

secret key estimation in sequential steganography we define sequential steganography as those class of embedding algorithms that hide messages in consecutive time spatial or frequency domain features of a host signal this work presents a steganalysis method that estimates the secret key used in sequential embedding steganalysis is posed as the detection of abrupt jumps in the statistics of a stego signal stationary and nonstationary host signals with low medium and high signal to noise ratio snr embedding are considered a locally most powerful steganalysis detector for the low snr case is also derived several techniques to make the steganalysis algorithm work for nonstationary digital image steganalysis are also presented extensive experimental results are shown to illustrate the strengths and weaknesses of the proposed steganalysis algorithm

periodic boundary value problems for first order functional differential equations with impulse by applying the well known fixed point theorem of cone expansion and compression this paper investigates the existence of multiple positive solutions of periodic boundary value problems for first order functional differential equations with impulse meanwhile four examples are worked out to demonstrate the main results

impulsive semilinear differential inclusions topological structure of the solution set and solutions on non compact domains abstract this paper deals with an impulsive cauchy problem governed by the semilinear evolution differential inclusion x t a t x t f t x t where a t t 0 b is a family of linear operators not necessarily bounded in a banach space e generating an evolution operator and f is a caratheodory type multifunction first a theorem on the compactness of the set of all mild solutions for the problem is given then this result is applied to obtain the existence of mild solutions for the impulsive cauchy problem defined on non compact domains

the multiplicity of solutions for perturbed second order hamiltonian systems with impulsive effects abstract in this paper we study the existence of multiple solutions for a class of second order impulsive hamiltonian systems we give some new criteria for guaranteeing that the impulsive hamiltonian systems with a perturbed term have at least three solutions by using a variational method and some critical points theorems of b ricceri we extend and improve on some recent results finally some examples are presented to illustrate our main results

an application of variational method to second order impulsive differential equation on the half line abstract in this paper we study the multiplicity of solutions for second order impulsive differential equation with a parameter on the half line by using a variational method and a three critical points theorem we give some new criteria to guarantee that the impulsive problem has at least three classical solutions also an example is given in this paper to illustrate the main results

closure properties for integral problems driven by regulated functions via convergence results abstract in this paper we give necessary and sufficient conditions for the convergence of kurzweil stieltjes integrals with respect to regulated functions using the notion of asymptotical equiintegrability one thus generalizes several well known convergence theorems as applications we provide existence and closure results for integral problems driven by regulated functions both in single and set valued cases in the particular setting of bounded variation functions driving the equations we get features of the solution set of measure integrals problems

extremal solutions of quasilinear parabolic inclusions with generalized clarke s gradient abstract in this paper we consider an initial boundary value problem for a parabolic inclusion whose multivalued nonlinearity is characterized by clarke s generalized gradient of some locally lipschitz function and whose elliptic operator may be a general quasilinear operator of leray lions type recently extremality results have been obtained in case that the governing multivalued term is of special structure such as multifunctions given by the usual subdifferential of convex functions or subgradients of so called dc functions the main goal of this paper is to prove the existence of extremal solutions within a sector of appropriately defined upper and lower solutions for quasilinear parabolic inclusions with general clarke s gradient the main tools used in the proof are abstract results on nonlinear evolution equations regularization comparison truncation and special test function techniques as well as tools from nonsmooth analysis

asymptotic behavior of linear impulsive integro differential equations asymptotic equilibria of linear integro differential equations and asymptotic relations between solutions of linear homogeneous impulsive differential equations and those of linear integro differential equations are established a new gronwall bellman type lemma for integro differential inequalities is proved an example is given to demonstrate the validity of one of the results

the existence and multiplicity of solutions for an impulsive differential equation with two parameters via a variational method abstract in this paper we study the existence and multiplicity of classical solutions for a second order impulsive differential equation with periodic boundary conditions by using a variational method and critical point theory we give some new criteria to guarantee that the impulsive problem has at least one solution two solutions and infinitely many solutions when the parameter pair c lies in different intervals respectively some examples are given in this paper to illustrate the main results

the zero rate spread spectrum watermarking game this paper develops a game theoretic methodology to design and embed m messages in signals and images in the presence of an adversary here m is assumed to be subexponential in the signal s sample size zero rate transmission and the embedding is done using spread spectrum watermarking the detector performs statistical hypothesis testing the system is designed to minimize probability of error under the worst case attack in a prescribed class of attacks the variables in this game are probability distributions for the watermarker and attacker analytical solutions are derived under the assumption of gaussian host vectors watermarks and attacks and squared error distortion constraints for the watermarker and the attacker the karhunen loeve transform klt plays a central role in this study the optimal distributions for the watermarker and the attacker are gaussian test channels applied to the klt coefficients the game is then reduced to a maxmin power allocation problem between the channels as a byproduct of this analysis we can determine the optimal tradeoff between using the most efficient in terms of detection performance signal components for transmission and spreading the transmission across many components to fool the attacker s attempts to eliminate the watermark we also conclude that in this framework additive watermarks are suboptimal they are however nearly optimal in a small distortion regime the theory is applied to watermarking of autoregressive processes and to wavelet based image watermarking the optimal watermark design outperforms conventional designs based on heuristic power allocations and or simple correlation detectors

existence and uniqueness results for impulsive functional differential equations with scalar multiple delay and infinite delay abstract in this paper we discuss local and global existence and uniqueness results for first order impulsive functional differential equations with multiple delay we shall rely on a nonlinear alternative of leray schauder for the global existence and uniqueness we apply a recent nonlinear alternative of leray schauder type in frechet spaces due to m frigon and a granas resultats de type leray schauder pour des contractions sur des espaces de frechet ann sci math quebec 22 2 1998 161 168 the goal of this paper is to extend the problems considered by a ouahab local and global existence and uniqueness results for impulsive differential equations with multiple delay j math anal appl 323 2006 456 472

periodic solutions for nonlinear differential inclusions with multivalued perturbations abstract in this paper the periodic solutions for nonlinear differential inclusion governed by convex subdifferential and different perturbations are studied it is firstly proved that the differential inclusion has unique periodic solution if the perturbation function is a single valued function then by schauder s fixed point theorem and kakutani s fixed point theorem we prove that the differential inclusion has at least a periodic solution when the perturbation function is an upper semicontinuous or lower semicontinuous multifunction moreover the existence of the extremal solution for the differential inclusion is also studied finally based on one sided lipschitz osl assumption we prove the related relaxation theorem

impulsive periodic boundary value problems of first order differential equations in this paper by using schaeffer s theorem we prove new existence theorems for a nonlinear periodic boundary value problem of first order differential equations with impulses our results improve and generalize some known results

contourlet based image watermarking using optimum detector in a noisy environment in this paper an improved multiplicative image watermarking system is presented since human visual system is less sensitive to the image edges watermarking is applied in the contourlet domain which represents image edges sparsely in the presented scheme watermark data is embedded in directional subband with the highest energy by modeling the contourlet coefficients with general gaussian distribution ggd the distribution of watermarked noisy coefficients is analytically calculated the tradeoff between the transparency and robustness of the watermark data is solved in a novel fashion at the receiver based on the maximum likelihood ml decision rule an optimal detector by the aid of channel side information is proposed in the next step a blind extension of the suggested algorithm is presented using the patchwork idea experimental results confirm the superiority of the proposed method against common attacks such as additive white gaussian noise awgn jpeg compression and rotation attacks in comparison with the recently proposed techniques

machine learning based adaptive watermark decoding in view of anticipated attack we present an innovative scheme of blindly extracting message bits when a watermarked image is distorted in this scheme we have exploited the capabilities of machine learning ml approaches for nonlinearly classifying the embedded bits the proposed technique adaptively modifies the decoding strategy in view of the anticipated attack the extraction of bits is considered as a binary classification problem conventionally a hard decoder is used with the assumption that the underlying distribution of the discrete cosine transform coefficients do not change appreciably however in case of attacks related to real world applications of watermarking such as jpeg compression in case of shared medical image warehouses these coefficients are heavily altered the sufficient statistics corresponding to the maximum likelihood based decoding process which are considered as features in the proposed scheme overlap at the receiving end and a simple hard decoder fails to classify them properly in contrast our proposed ml decoding model has attained highest accuracy on the test data experimental results show that through its training phase our proposed decoding scheme is able to cope with the alterations in features introduced by a new attack consequently it achieves promising improvement in terms of bit correct ratio in comparison to the existing decoding scheme

existence theorems of global solutions of initial value problems for nonlinear integrodifferential equations of mixed type in banach spaces and applications abstract this paper investigates the existence of global solutions for initial value problems of the nonlinear integrodifferential equations in banach spaces we obtain the existence of global solutions by schauder s fixed point theorem our results are the generalizations and improvements of recent results as applications of our results the existence of global solutions of two classes of third order mixed boundary value problem is obtained and an example of infinite system for nonlinear integrodifferential equations is worked out to illustrate our main results