computation theory of cellular automata self organizing behaviour in cellular automata is discussed as a computational process formal language theory is used to extend dynamical systems theory descriptions of cellular automata the sets of configurations generated after a finite number of time steps of cellular automaton evolution are shown to form regular languages many examples are given the sizes of the minimal grammars for these languages provide measures of the complexities of the sets this complexity is usually found to be non decreasing with time the limit sets generated by some classes of cellular automata correspond to regular languages for other classes of cellular automata they appear to correspond to more complicated languages many properties of these sets are then formally non computable it is suggested that such undecidability is common in these and other dynamical systems

further relaxations of the semidefinite programming approach to sensor network localization recently a semidefinite programming sdp relaxation approach has been proposed to solve the sensor network localization problem although it achieves high accuracy in estimating the sensor locations the speed of the sdp approach is not satisfactory for practical applications in this paper we propose methods to further relax the sdp relaxation more precisely to relax the single semidefinite matrix cone into a set of small size semidefinite submatrix cones which we call a sub sdp ssdp approach we present two such relaxations although they are weaker than the original sdp relaxation they retain the key theoretical property and numerical experiments show that they are both efficient and accurate the speed of the ssdp is even faster than that of other approaches based on weaker relaxations the ssdp approach may also pave a way to efficiently solving general sdp problems without sacrificing the solution quality

digital mechanics an informational process based on reversible universal cellular automata abstract this paper is written from the perspective of a computer scientist and addressed to theoretical physicists as a consequence it may seem somewhat unusual but rest assured everything is really quite simple the point of this paper is that the study of certain phenomena from computer science suggests that there are computer systems cellular automata that may be appropriate as models for microscopic physical phenomena cellular automata are now being used to model varied physical phenomena normally modelled by wave equations fluid dynamics ising models etc we hypothesize that there will be found a single cellular automaton rule that models all of microscopic physics and models it exactly we call this field dm for digital mechanics

a new steganography method which preserves histogram generalization of lsb histogram based steganalysis methods diagnose abnormalities in the stego histogram lsb and outguess are two steganography methods which preserve the cover histogram completely these methods embed some extra bits to retain the cover histogram however these techniques adversely affect the statistical and perceptual attributes of the cover media lsb was proposed to improve lsb by prohibiting some pixels from changing resulting in the reduction of the extra bits in this paper we improve the lsb method by proposing a technique to distinguish sensitive pixels and protect them from extra bit embedding which causes lower distortion in the co occurrence matrices in addition we extend lsb to preserve the dct coefficients histogram of jpeg images and generalize this method to the case where more than one bit of the cover elements are used the experimental results show that the improved lsb method produces fewer traces in the co occurrence matrices than the lsb method furthermore the histogram based attacks cannot detect stego images produced by the proposed method with or without extra bits embedding therefore the visual quality of the cover can be improved by the elimination of extra bit embedding

cooling schedules for optimal annealing a monte carlo optimization technique called simulated annealing is a descent algorithm modified by random ascent moves in order to escape local minima which are not global minima the level of randomization is determined by a control parameter t called temperature which tends to zero according to a deterministic cooling schedule we give a simple necessary and sufficient condition on the cooling schedule for the algorithm state to converge in probability to the set of globally minimum cost states in the special case that the cooling schedule has parametric form tt c log1 t the condition for convergence is that c be greater than or equal to the depth suitably defined of the deepest local minimum which is not a global minimum state

diffusions for global optimizations we seek a global minimum of u 0 1 n to r the solution to d dt x t nabla u x t will find local minima the solution to dx t nabla u x t dt sqrt 2t dw t where w is standard n dimensional brownian motion and the boundaries are reflecting will concentrate near the global minima of u at least when temperature t is small the equilibrium distribution for x t is gibbs with density pi t x alpha exp u x t this suggests setting t t t downarrow 0 to find the global minima of u we give conditions on u x and t t such that the solution to dx t nabla u x t dt sqrt 2t dw t converges weakly to a distribution concentrated on the global minima of u

data embedding for vector quantization image processing on the basis of adjoining state codebook mapping information hiding for images is an important research issue in digital multimedia it provides a way to certify copyrights of image files as well as a means of secret communication for people in this paper we propose a reversible image information hiding scheme based on vector quantization vq the proposed scheme uses a new technique called adjoining state codebook mapping ascm to map the content of an image block to an index in the corresponding state codebooks the ascm technique uses two adjacent image blocks of an encoding image block to create two state codebooks which can represent the encoding image block more accurately therefore it can reduce the size of the output code stream and yet still provide large embedding capacity for secret data experimental results indicate that the proposed scheme has better compression bit rate and larger embedding capacity when we compare the proposed scheme with recent similar studies proposed by chang et al in 2009 and yang et al in 2011 respectively

positive semidefinite matrix completion universal rigidity and the strong arnold property this paper addresses the following three topics positive semidenite psd matrix completions universal rigidity of frameworks and the strong arnold property sap we show some strong connections among these topics using semidenite programming as unifying theme our main contribution is a sufcient condition for constructing partial psd matrices which admit a unique completion to a full psd matrix such partial matrices are an essential tool in the study of the gram dimension gd g of a graph g a recently studied graph parameter related to the low psd matrix completion problem additionally we derive an elementary proof of connelly s sucient condition for universal rigidity of tensegrity frameworks and we investigate the links between these two sucient conditions we also give a geometric characterization of psd matrices satisfying the strong arnold property in terms of nondegeneracy of an associated semidenite program which we use to establish some links between the gram dimension gd and the colin de verdi ere type graph parameter

an adaptive secret image sharing with a new bitwise steganographic property recently numerous studies have been conducted in the area of secret image sharing and steganography the main objective of these schemes is to produce high quality tampering resistant stego images a number of these methods are based on least significant bit embedding and hence the presence of hidden data can be detected by well designed steganalysis algorithms this paper proposes a new sharing scheme for critical images so that stego images are obtained with better visual quality and at the same time the authentication ability can be adjusted to any desired level adaptive in order to achieve these objectives the construction of cellular automata is modified so that visual quality is improved although authentication bits are hidden in cover images furthermore authentication bits are computed in such a way that any tampering with one block affects more than one block for steganographic purposes least significant bit replacement is substituted with a new blockwise xor operation so that the scheme can withstand steganalysis attacks the other interesting property of the proposed method is that the size of blocks is determined dynamically therefore our approach can be adapted with secret cover images of different sizes

characterizing generic global rigidity a d dimensional framework is a graph and a map from its vertices to ed such a framework is globally rigid if it is the only framework in ed with the same graph and edge lengths up to rigid motions for which underlying graphs is a generic framework globally rigid we answer this question by proving a conjecture by connelly that his sucient condition is also necessary the condition comes from considering the geometry of the length squared mapping essentially the graph is generically locally rigid i the rank of is maximal and it is generically globally rigid i the rank of the gauss map on the image of is maximal we also show that this condition is eciently checkable with a randomized algorithm

parameter estimation of nonlinear systems by dynamic cuckoo search in order to address with the problem of the traditional or improved cuckoo search cs algorithm we propose a dynamic adaptive cuckoo search with crossover operator dacs co algorithm normally the parameters of the cs algorithm are kept constant or adapted by empirical equation that may result in decreasing the efficiency of the algorithm in order to solve the problem a feedback control scheme of algorithm parameters is adopted in cuckoo search rechenberg s 1 5 criterion combined with a learning strategy is used to evaluate the evolution process in addition there are no information exchanges between individuals for cuckoo search algorithm to promote the search progress and overcome premature convergence the multiple point random crossover operator is merged into the cs algorithm to exchange information between individuals and improve the diversification and intensification of the population the performance of the proposed hybrid algorithm is investigated through different nonlinear systems with the numerical results demonstrating that the method can estimate parameters accurately and efficiently finally we compare the results with the standard cs algorithm orthogonal learning cuckoo search algorithm olcs an adaptive and simulated annealing operation with the cuckoo search algorithm acs sa a genetic algorithm ga a particle swarm optimization algorithm pso and a genetic simulated annealing algorithm ga sa our simulation results demonstrate the effectiveness and superior performance of the proposed algorithm

lsb steganographic method based on reversible histogram transformation function for resisting statistical steganalysis statistical steganalysis schemes detect the existence of secret information embedded by steganography the x 2 detection and regular singular rs attack methods are two well known statistical steganalysis schemes used against lsb least significant bit steganography the embedded message length can be estimated accurately by these two steganalysis schemes for secret communication the resistance of steganography against steganalysis is very important for information security to avoid the enemy s attempts the statistical features between stego images and cover images should be as similar as possible for better resistance to steganalysis in this manuscript a reversible histogram transformation function based lsb steganographic method is proposed to resist statistical steganalysis the experimental results show that the proposed method resists not only rs attack but also x 2 detection methods

invertible cellular automata a review abstract in the light of recent developments in the theory of invertible cellular automata we attempt to give a unified presentation of the subject and discuss its relevance to computer science and mathematical physics

hiding data in images by simple lsb substitution in this paper a data hiding scheme by simple lsb substitution is proposed by applying an optimal pixel adjustment process to the stego image obtained by the simple lsb substitution method the image quality of the stego image can be greatly improved with low extra computational complexity the worst case mean square error between the stego image and the cover image is derived experimental results show that the stego image is visually indistinguishable from the original cover image the obtained results also show a significant improvement with respect to a previous work

sharing secrets in stego images with authentication recently lin and tsai and yang et al proposed secret image sharing schemes with steganography and authentication which divide a secret image into the shadows and embed the produced shadows in the cover images to form the stego images so as to be transmitted to authorized recipients securely in addition these schemes also involve their authentication mechanisms to verify the integrity of the stego images such that the secret image can be restored correctly unfortunately these schemes still have two shortcomings one is that the weak authentication cannot well protect the integrity of the stego images so the secret image cannot be recovered completely the other shortcoming is that the visual quality of the stego images is not good enough to overcome such drawbacks in this paper we propose a novel secret image sharing scheme combining steganography and authentication based on chinese remainder theorem crt the proposed scheme not only improves the authentication ability but also enhances the visual quality of the stego images the experimental results show that the proposed scheme is superior to the previously existing methods

robust edge based semidefinite programming relaxation of sensor network localization recently wang zheng boyd and ye siam j optim 19 655 673 2008 proposed a further relaxation of the semidefinite programming sdp relaxation of the sensor network localization problem named edge based sdp esdp in simulation the esdp is solved much faster by interior point method than sdp relaxation and the solutions found are comparable or better in approximation accuracy we study some key properties of the esdp relaxation showing that when distances are exact zero individual trace is not only sufficient but also necessary for a sensor to be correctly positioned by an interior solution we also show via an example that when distances are inexact zero individual trace is insufficient for a sensor to be accurately positioned by an interior solution we then propose a noise aware robust version of esdp relaxation for which small individual trace is necessary and sufficient for a sensor to be accurately positioned by a certain analytic center solution assuming the noise level is sufficiently small for this analytic center solution the position error for each sensor is shown to be in the order of the square root of its trace lastly we propose a log barrier penalty coordinate gradient descent method to find such an analytic center solution in simulation this method is much faster than interior point method for solving esdp and the solutions found are comparable in approximation accuracy moreover the method can distribute its computation over the sensors via local communication making it practical for positioning and tracking in real time

universality and complexity in cellular automata abstract cellular automata are discrete dynamical systems with simple construction but complex self organizing behaviour evidence is presented that all one dimensional cellular automata fall into four distinct universality classes characterizations of the structures generated in these classes are discussed three classes exhibit behaviour analogous to limit points limit cycles and chaotic attractors the fourth class is probably capable of universal computation so that properties of its infinite time behaviour are undecidable

a secret sharing scheme based on cellular automata a new secret sharing scheme based on a particular type of discrete delay dynamical systems memory cellular automata is proposed specifically such scheme consists of a k n threshold scheme where the text to be shared is considered as one of the k initial conditions of the memory cellular automata and the n shares to be distributed are n consecutive configurations of the evolution of such cellular automata it is also proved to be perfect and ideal

cellular automata as an alternative to rather than an approximation of differential equations in modeling physics abstract cellular automata are models of distributed dynamical systems whose structure is particularly well suited to ultrafast exact numerical simulation on the other hand they constitute a radical departure from the traditional partial differential equation approach to distributed dynamics here we discuss the problem of encoding the state variables and evolution laws of a physical system into this new setting and of giving suitable correspondence rules for interpreting the model s behavior

steganalysis classifier training via minimizing sensitivity for different imaging sources owing to the ever proliferation of digital cameras and image editing software a large variety of jpeg quantization tables are used to compress jpeg images as a result learning based steganalysis methods using a pre selected quantization table for training images degrade significantly when the quantization table of testing images is different from the one used for training recognizing that it would be undesirable and not practical to train a steganalysis classifier with all possible quantization tables we propose an approach that the differences in features extracted from images with different quantization tables are formulated as perturbations of those features then we define a stochastic sensitivity by the expected square of classifier output changes with respect to these feature perturbations to compute the robustness of classifiers with respect to perturbations a radial basis function neural network based steganalysis classifier trained by minimizing the sensitivity is proposed experimental results show that the proposed method outperforms learning methods such as support vector machine and radial basis function neural network without considering feature perturbations

physics like models of computation abstract reversible cellular automata are computer models that embody discrete analogues of the classical physics notions of space time locality and microscopic reversibility they are offered as a step towards models of computation that are closer to fundamental physics

image complexity and feature mining for steganalysis of least significant bit matching steganography the information hiding ratio is a well known metric for evaluating steganalysis performance in this paper we introduce a new metric of image complexity to enhance the evaluation of steganalysis performance in addition we also present a scheme of steganalysis of least significant bit lsb matching steganography based on feature mining and pattern recognition techniques compared to other well known methods of steganalysis of lsb matching steganography our method performs the best results also indicate that the significance of features and the detection performance depend not only on the information hiding ratio but also on the image complexity

two verifiable multi secret sharing schemes based on nonhomogeneous linear recursion and lfsr public key cryptosystem we shall propose two new efficient verifiable multi secret sharing schemes based on linear feedback shift register lfsr public key and new nonhomogeneous linear recursions compared with previous schemes these schemes have better performance and shorter private public key length moreover they have fewer public values and simpler construction as well as various methods for the reconstruction phase altogether they are easy to use and provide great capabilities for many applications

graph rigidity via euclidean distance matrices abstract let g v e be an incomplete graph with node set v edge set e and nonnegative weights ij s on the edges let each edge v i v j be viewed as a rigid bar of length ij which can rotate freely around its end nodes a realization of a graph g is an assignment of coordinates in some euclidean space to each node of g in this paper we consider the problem of determining whether or not a given realization of a graph g is rigid we show that each realization of g can be epresented as a point in a compact convex set r m and that a generic realization of g is rigid if and only if its corresponding point is a vertex of i e an extreme point with full dimensional normal cone

universally ideal secret sharing schemes given a set of parties 1 spl middot spl middot spl middot n an access structure is a monotone collection of subsets of the parties for a certain domain of secrets a secret sharing scheme for an access structure is a method for a dealer to distribute shares to the parties these shares enable subsets in the access structure to reconstruct the secret while subsets not in the access structure get no information about the secret a secret sharing scheme is ideal if the domains of the shares are the same as the domain of the secrets an access structure is universally ideal if there exists an ideal secret sharing scheme for it over every finite domain of secrets an obvious necessary condition for an access structure to be universally ideal is to be ideal over the binary and ternary domains of secrets the authors prove that this condition is also sufficient they also show that being ideal over just one of the two domains does not suffice for universally ideal access structures finally they give an exact characterization for each of these two conditions

a new efficient t n verifiable multi secret sharing vmss based on ych scheme a verifiable multi secret sharing scheme vmss is a multi secret sharing scheme with the verifiable property this paper presents a new efficient verifiable multi secret sharing based on ych c c yang t y chang m s hwang a t n multi secret sharing scheme appl math comput 151 2004 483 490 scheme and the intractability of the discrete logarithm dl and it just needs few public values and low modular exponentiation operation

on bar frameworks stress matrices and semidefinite programming a bar framework g p in r dimensional euclidean space is a graph g on the vertices 1 2 n where each vertex i is located at point p i in mathbb r r given a framework g p in mathbb r r a problem of great interest is that of determining whether or not there exists another framework g q not obtained from g p by a rigid motion such that q i q j 2 p i p j 2 for each edge i j of g this problem is known as either the global rigidity problem or the universal rigidity problem depending on whether such a framework g q is restricted to be in the same r dimensional space or not the stress matrix s of a bar framework g p plays a key role in these and other related problems in this paper semidefinite programming sdp theory is used to address in a unified manner several problems concerning universal rigidity new results are presented as well as new proofs of previously known theorems in particular we use the notion of sdp non degeneracy to obtain a sufficient condition for universal rigidity and we show that this condition yields the previously known sufficient condition for generic universal rigidity we present new results concerning positive semidefinite stress matrices and we use a semidefinite version of farkas lemma to characterize bar frameworks that admit a nonzero positive semidefinite stress matrix s

levy flights in a steep potential well levy flights in steeper than harmonic potentials have been shown to exhibit finite variance and a critical time at which a bifurcation from an initial monomodal to a terminal bimodal distribution occurs chechkin et al phys rev e 67 010102 r 2003 in this paper we present a detailed study of levy flights in potentials of the type u x x c with c 2 apart from the bifurcation into bimodality we find the interesting result that for c 4 a trimodal transient exists due to the temporal overlap between the decay of the central peak around the initial condition and the building up of the two emerging side peaks which are characteristic for the stationary state thus for certain system parameters there exists a transient trimodal distribution of the levy flight these properties of levy flights in external potentials of the power law type can be represented by certain phase diagrams we also present details about the proof of multimodality and the numerical procedures to establish the probability distribution of the process

complementarity and nondegeneracy in semidefinite programming primal and dual nondegeneracy conditions are defined for semidefinite programming given the existence of primal and dual solutions it is shown that primal nondegeneracy implies a unique dual solution and that dual nondegeneracy implies a unique primal solution the converses hold if strict complementarity is assumed primal and dual nondegeneracy assumptions do not imply strict complementarity as they do in lp the primal and dual nondegeneracy assumptions imply a range of possible ranks for primal and dual solutions x and z this is in contrast with lp where nondegeneracy assumptions exactly determine the number of variables which are zero it is shown that primal and dual nondegeneracy and strict complementarity all hold generically numerical experiments suggest probability distributions for the ranks of x and z which are consistent with the nondegeneracy conditions

adaptive image data hiding in edges using patched reference table and pair wise embedding technique reference table rt based embedding method embeds secret digits into pixel pairs under the guidance of a reference table most of the existing rt based methods either require elaborate conversions among different bases or have limited embedding capacity in this paper we use a patched reference table prt as a guide and propose a prt method to provide a better image quality and extendable embedding capacity we also exploit the concept of pixel value differencing pvd and propose another method prt pvd in the traditional pvd based methods the shape of the difference histograms of the stego images is significantly altered and thus vulnerable to some steganalyzers prt pvd adopts the prt method and uses a specially designed embedding sequence to preserve the difference histogram shape experimental results reveal that the proposed prt and prt pvd methods not only have better embedding efficiency over the existing methods but also are robust to detection by modern steganalysis tools

a t n multi secret sharing scheme in the t n multi secret sharing scheme there are n participants in the system at least t or more participants can easily pool their secrets shadows and reconstruct p secrets at the same time chien et al ieice trans fundamentals e83 a 2000 2762 used n p t 1 public values 2 n p t x n p storages and solved n p t simultaneous equations to share p secrets in this article we shall propose an alternative t n multi secret sharing based on shamir s secret sharing we shall use n p t 1 or n 1 public values 2 t 1 or 2 p 1 storages and employ the lagrange interpolation polynomial to share p secrets our scheme will have exactly the same power as chien et al s scheme

distortionless visual multi secret sharing based on random grid we proposed an visual multi secret sharing without secret distortion we define the shape of share as pie not traditional doughnut shape number of secret sharing is more than two we adopt rg based for implementing vmss to void pixel expansion and complex codebook design because visual secret sharing vss has already been well defined visual multi secret sharing vmss is more practical for various fields in a vmss scheme n secret messages are encoded into two shares that appear to be noise and these are later stacked by rotating flipping and turning to visually recognize the secrets vmss is generally classified as visual cryptography vc based vmss or random grid rg based vmss however vc based vmss has the three main drawbacks of pixel expansion the cost of designing a complex codebook and shape distortion in the decoded secret image in order to stack shares at any angle during decoding secrets are encoded into doughnut shaped shares however the traditional doughnut share methods distort the secret after decoding because the shape of each share is doughnut this paper proposes a new rg based vmss scheme that defines the shape of each share as a pie shaped share that does not distort secrets so that multiple secrets are encoded into two pie shares and then decoded by stacking one pie share on another at different angles of rotation experimental results demonstrate the efficiency of the proposed method

new efficient and practical verifiable multi secret sharing schemes in 2006 zhao et al proposed a practical verifiable multi secret sharing based on yang et al s and feldman s schemes in this paper we propose two efficient computationally secure t n and verifiable multi secret sharing schemes based on homogeneous linear recursion the first scheme has the advantage of better performance a new simple construction and various techniques for the reconstruction phase the second scheme requires fewer public values with respect to zhao et al s and shao and cao schemes these schemes are easy to implement and provide great capabilities for many applications

directed transport induced by spatially modulated levy flights in this paper we study the dynamics of a particle in a ratchet potential subject to multiplicative stable levy noise in the limit of a noise amplitude we compare the dynamics for ito and marcus multiplicative noises and obtain the explicit asymptotics of the escape time in the wells and transition probabilities between the wells a detailed analysis of the noise induced current is performed for the seebeck ratchet with a weak multiplicative noise for

efficient verifiable multi secret sharing scheme based on hash function abstract a verifiable k t n multi secret sharing scheme vmss allows a dealer to share k secrets among n players in particular 1 the secret shadow given by the dealer or some player can be verifiable and 2 t or more players can cooperate to reveal the k secrets while less than t players cannot reveal any secret vmss can be used in many applications such as access control however the existing vmss schemes either require costly computation or miss some important properties of vmss these two weaknesses make the vmss scheme not so good as expected in this paper we propose a novel vmss scheme which does not need any costly computation while holds all properties of vmss

diffusion for global optimization in r n we seek a global minimum of u mathbb r n to mathbb r the solution to d dt x t nabla u x t will find local minima using the idea of simulated annealing we consider th

a multisecret sharing scheme for color images based on cellular automata in this work a new multisecret sharing scheme for secret color images among a set of users is proposed the protocol allows that each participant in the scheme to share a secret color image with the rest of participants in such a way that all of them can recover all the secret color images only if the whole set of participants pools their shadows the proposed scheme is based on the use of bidimensional reversible cellular automata with memory the security of the scheme is studied and it is proved that the protocol is ideal and perfect and that it resists the most important statistical attacks

levy flights transitions and meta stability we consider l vy flights of stability index 0 2 in a potential landscape in the limit of a small noise parameter we give a purely probabilistic description of the random dynamics on the basis of a special decomposition of the driving l vy processes into independent small jumps and compound poisson parts we prove that escape times from a potential well are exponentially distributed and their mean values increase as a power of the noise intensity this allows us to obtain meta stability results for a jump diffusion in a double well potential

necessary and sufficient graphical conditions for affine formation control this paper introduces a new multi agent control problem called an affine formation control problem with the objective of asymptotically reaching a configuration that preserves collinearity and ratios of distances with respect to a target configuration suppose each agent updates its own state using a weighted sum of its neighbor s relative states with possibly negative weights then the affine control problem can be solved for either undirected or directed interaction graphs it is shown in this paper that an affine formation is stabilizable over an undirected graph if and only if the undirected graph is universally rigid while an affine formation is stabilizable over a directed graph in the d dimensional space if and only if the directed graph is d 1 rooted rigorous analysis is provided mainly relying on laplacian associated with the interaction graph which contain both positive and negative weights

an improvement on the lin wu t n threshold verifiable multi secret sharing scheme lin and wu iee proc comput digit tech 146 1999 264 have proposed an efficient t n threshold verifiable multi secret sharing vmss scheme based on the factorization problem and the discrete logarithm modulo a large composite problem in their scheme the dealer can arbitrarily give any set of multiple secrets to be shared and only one reusable secret shadow is to be kept by every participant on the other hand they have claimed that their scheme can provide an efficient solution to the cheating problems between the dealer and any participant however he and wu iee proc comput digit tech 148 2001 139 have shown that lin and wu s scheme is in fact insecure against a cheating participant in this paper we shall try to improve the security of lin and wu s scheme while providing more efficient performance than other vmss schemes in terms of computational complexity

a simple and high hiding capacity method for hiding digit by digit data in images based on modulus function this study presents a simple method for high hiding capacity the basic concept uses a modulus operation the proposed method has the following advantages 1 the proposed method outperforms the simple lsb substitution method given the same range 0 m 1 of data digits in the embedded data 2 the proposed method achieves good image vision quality without the need for post processing 3 the proposed method is almost as simple as the lsb method in both coding and decoding 4 the smaller error advantage over the simple lsb substitution method can also be mathematically verified 5 the error is smaller than m 1 2 for almost every pixel 6 the proposed method has high hiding capacity for example the proposed method can hide a 256 256 or 256 512 image in a 512 512 host image

lossless data hiding for vq indices based on neighboring correlation data hiding is one of the protective techniques for authentication or secret communication through a public and open channel such as the internet in this study a novel lossless data hiding by embedding secret data into a vector quantization vq compressed image is proposed to achieve secret communication and data compression simultaneously the correlation of neighboring blocks of a vq compressed image is explored it is shown that the neighboring blocks of a vq compressed image normally have high mutual correlation thus this scheme employs the neighboring processed compression indices to generate specific sub codebooks required for encoding and hiding data simultaneously since the sizes of sub codebooks are smaller than that of the original vq codebook the encoded size of each index can be significantly reduced as a result a great deal of extra free space can be created moreover the original vq compressed images can be perfectly recovered after data extraction to evaluate the effectiveness of this approach various test images are employed in the experiments as documented in the experimental results it is shown that the performance of the proposed scheme is superior to the former schemes in terms of compression ratio embedding rate execution time and embedding capacity

image hiding scheme with modulus function and dynamic programming strategy on partitioned pixels in this paper we shall propose a novel image hiding scheme our new scheme classifies the host image pixels into two groups of pixels according to the pixel values for each group of pixels the corresponding secret pixel values go through an optimal substitution process and are transformed into other pixel values by following the dynamic programming strategy then we can embed the transformed pixel values in the host pixels by using the modulus functions and obtain the stego image extensive experimental results demonstrate that our new method is capable of offering better stego image quality than a number of well accepted schemes

on affine motions and universal rigidity of tensegrity frameworks abstract recently alfakih and ye 2013 4 proved that if an r dimensional bar framework g p on n r 2 nodes in general position in r r admits a positive semidefinite stress matrix with rank n r 1 then g p is universally rigid in this paper we generalize this result in two directions first we extend this result to tensegrity frameworks second we replace the general position assumption by the weaker assumption that in configuration p each point and its neighbors in g affinely span r r

invertible behavior in elementary cellular automata with memory elementary cellular automata ecas have been studied for their ability to generate complex global behavior despite their simplicity one variation of ecas is obtained by adding memory to each cell in a neighborhood this process generates a provisional configuration in which the application of an evolution rule establishes the dynamics of the system this version is known as an eca with memory ecam most previous work on ecams analyzed the complex behavior taking chaotic ecas however the present paper investigates reversible ecams as obtained from reversible and permutative ecas these ecas have at least one ancestor for every configuration thus the correct permutation of states may specify the memory function to obtain reversible ecams for permutative ecas which are often irreversible we demonstrate that the use of a quiescent state and the correct manipulation of de bruijn blocks produce reversible ecams

reversible cellular automata with memory two dimensional patterns from a single site seed standard cellular automata ca are ahistoric memoryless i e the new state of a cell depends on its neighborhood configuration only at the preceding time step historic memory of all past iterations can be incorporated into ca by featuring each cell by a weighted mean of all its past states in this paper a new kind of reversible ca which incorporates memory is introduced in a two dimensional scenario

finding optimal least significant bit substitution in image hiding by dynamic programming strategy abstract the processing of simple least significant bit lsb substitution embeds the secret image in the least significant bits of the pixels in the host image this processing may degrade the host image quality so significantly that grabbers can detect that there is something going on in the image that interests them to overcome this drawback an exhaustive least significant bit substitution scheme was proposed by wang et al but it takes huge computation time wang et al then proposed another method that uses a genetic algorithm to search approximate optimal solutions and computation time is no longer so huge in this paper we shall use the dynamic programming strategy to get the optimal solution the experimental results will show that our method consumes less computation time and also gets the optimal solution

first passage time moments of asymmetric levy flights we investigate the first passage dynamics of symmetric and asymmetric l evy flights in a semi infinite and bounded intervals by solving the space fractional diffusion equation we analyse the fractional order moments of the first passage time probability density function for different values of the index of stability and the skewness parameter a comparison with results using the langevin approach to l evy flights is presented for the semi infinite domain in certain special cases analytic results are derived explicitly and in bounded intervals a general analytical expression for the mean first passage time of l evy flights with arbitrary skewness is presented these results are complemented with extensive numerical analyses

asymptotics of the spectral gap with applications to the theory of simulated annealing soit m une variete de riemann compacte connexe a n dimensions de produit interieur et soit u m r 1 une fonction lisse donnee pour 0 on definit 7b l c m c m par 7b l o exp u exp u o ou et sont le gradient et la divergence sur m soit la taille de l ecart entre 0 et le reste du spectre de 7b l on etudie le comportement asymptotique de

a modular approach to key safeguarding a method is proposed for a key safeguarding scheme threshold scheme in which the shadows are congruence classes of a number associated with the original key a variation of this scheme provides efficient error detection and even exposes deliberate tampering certain underlying similarities of this scheme with shamir s interpolation method make it possible to incorporate these protective features in that method as well

local structure theory for cellular automata abstract the mean field theory for cellular automata wolfram and schulman and seiden is generalized to the local structure theory the local structure theory is a sequence of finitely parameterized models of the statistical features of a cellular automaton s evolution the n th model in the sequence takes into account correlations in terms of the probability of blocks of n states a class of measures the n block measures is introduced the local structure operator of order n maps n block measures to n block measures in a manner which reflects the cellular automaton map on blocks of states the fixed points of the map on measures approximate the invariant measures of the cellular automaton the ability of the local structure theory to model evolution from uncorrelated initial distributions is studied the theory gives exact results in simple cases in more complex cases monte carlo numerical experiments suggest that an accurate statistical portrait of cellular automaton evolution is obtained the invariant measures of a cellular automaton and the stability of these measures may be obtained from the local structure theory the local structure theory appears to be a powerful method for characterization and classification of cellular automata nearest neighbor cellular automata with two states per cell are studied using this method

efficient visual secret sharing scheme for color images a k out of n visual secret sharing scheme vsss resolves the visual variant of the k out of n secret sharing problem where only k or more out of n participants can reveal the secret by human visual system without any cryptographic computation the best pixel expansion of the general k out of n vsss for c colored images was cxm by yang and laih new colored visual secret sharing schemes des codes cryptogr 24 2000 325 335 where m is the pixel expansion of an existing binary k out of n vsss regarding the c colored n out of n scheme the best pixel expansion is c 1 2 n 1 c 2 and c c 1 2 n 2 c when n is odd and even respectively by blundo et al improved schemes for visual cryptography des codes cryptogr 24 2001 255 278 in this paper we propose a new c colored k out of n vsss by using a pixel expansion of log 2c xm that is more efficient than ever

secret image sharing based on cellular automata and steganography recently lin and tsai secret image sharing with steganography and authentication the journal of systems and software 73 2004 405 414 and yang et al improvements of image sharing with steganography and authentication the journal of systems and software 80 2007 1070 1076 proposed secret image sharing schemes combining steganography and authentication based on shamir s polynomials the schemes divide a secret image into some shadows which are then embedded in cover images in order to produce stego images for distributing among participants to achieve better authentication ability chang et al sharing secrets in stego images with authentication pattern recognition 41 2008 3130 3137 proposed in 2008 an improved scheme which enhances the visual quality of the stego images as well and the probability of successful verification for a fake stego block is 1 16 in this paper we employ linear cellular automata digital signatures and hash functions to propose a novel t n threshold image sharing scheme with steganographic properties in which a double authentication mechanism is introduced which can detect tampering with probability 255 256 employing cellular automata instead of shamir s polynomials not only improves computational complexity from o nlog 2n to o n but obviates the need to modify pixels of cover images unnecessarily compared to previous methods c lin w tsai secret image sharing with steganography and authentication the journal of systems and software 73 2004 405 414 c yang t chen k yu c wang improvements of image sharing with steganography and authentication the journal of systems and software 80 2007 1070 1076 c chang y hsieh c lin sharing secrets in stego images with authentication pattern recognition 41 2008 3130 3137 we use fewer number of bits in each pixel of cover images for embedding data so that a better visual quality is guaranteed we further present some experimental results

on the effect of memory in one dimensional k 4 automata on networks the effect of implementing memory in cells of one dimensional ca and on nodes of various types of automata on networks with increasing degrees of random rewiring is studied in this article paying particular attention to the case of four inputs as a rule memory induces a moderation in the rate of changing nodes and in the damage spreading albeit in the latter case memory turns out to be ineffective in the control of the damage as the wiring network moves away from the ordered structure that features proper one dimensional ca this article complements the previous work done in the two dimensional context

near optimal solution to pair wise lsb matching via an immune programming strategy in this paper a novel steganographic method is proposed employing an immune programming strategy to find a near optimal solution for the pair wise least significant bit lsb matching scheme the lsb matching method proposed by mielikaien utilizes a binary function to reduce the number of changed pixel values however his method still has room for improvement a tier score system is proposed in this paper to assess the performance of different orders for lsb matching an immune programming approach is adopted to search for a near optimal solution among all the permutation orders the proposed method can reduce the distortion of the stego image improve the visual quality and decrease the probability of detection the experimental results show that the proposed method achieves better performance than mielikainen s pair wise lsb matching method in terms of distortion and survival probability against steganalysis

boolean derivatives on cellular automata abstract boolean derivatives are applied to cellular automata they extract the linear part of arbitrary rules and provide an intrinsic classification derivatives are applied to tracing complexity growth and to lattice gases a complete table of derivatives is given for one dimensional elementary cellular automata

on stress matrices of d 1 lateration frameworks in general position let g p be a bar framework of n vertices in general position in mathbb r d for d n 1 where g is a d 1 lateration graph in this paper we present a constructive proof that g p admits a positive semidefinite stress matrix with rank n d 1 we also prove a similar result for a sensor network where the graph consists of m d 1 anchors

metropolis type annealing algorithms for global optimization in r d the convergence of a class of metropolis type markov chain annealing algorithms for global optimization of a smooth function u cdot on mathbb r d is established no prior information is assumed as to what bounded region contains a global minimum the analysis contained herein is based on writing the metropolis type algorithm in the form of a recursive stochastic algorithm x k 1 x k a k nabla u x k xi k b k w k where w k is a standard white gaussian sequence xi k are random variables and a k a k b k sqrt b sqrt k log log k for k large convergence results for x k are then applied from our previous work siam journal on control and optimization 29 1991 pp 999 1018 since the analysis of x k is based on the asymptotic behavior of the related langevin type markov diffusion annealing algorithm dy t nabla u y t dt c t dw t where w cdot is a standard wiener process and c t

cellular automata in fuzzy backgrounds abstract the main purpose of this work is to understand some limitations introduced by the classical definitions of cellular automata ca to this end we have defined a new model of cas fuzzy ca s which allows the observation of interesting chaotic properties of elementary cas to date neither a formal nor a precise definition of chaos in cas exists we believe that the proposed model provides a sharper tool to detect which properties can be associated to a chaotic behavior we also define a measure rule entropy which gives information about the ca s dynamics solely on the basis of the rule table and provides theoretical explanations to some of the empirical observations

universal rigidity and edge sparsification for sensor network localization owing to their high accuracy and ease of formulation there has been great interest in applying convex optimization techniques particularly that of semidefinite programming sdp relaxation to tackle the sensor network localization problem in recent years however a drawback of such techniques is that the resulting convex program is often expensive to solve in order to speed up computation various edge sparsification heuristics have been proposed whose aim is to reduce the number of edges in the input graph although these heuristics do reduce the size of the convex program and hence make it faster to solve they are often ad hoc in nature and do not preserve the localization properties of the input as such one often has to face a tradeoff between solution accuracy and computational effort in this paper we propose a novel edge sparsification heuristic that can provably preserve the localization properties of the original input at the heart of our heuristic is a graph decomposition procedure which allows us to identify certain sparse generically universally rigid subgraphs of the input graph our computational results show that the proposed approach can significantly reduce the computational and memory complexities of sdp based algorithms for solving the sensor network localization problem moreover it compares favorably with existing speedup approaches both in terms of accuracy and solution time

sharing and hiding secret images with size constraint this paper presents a method for sharing and hiding secret images the method is modified from the t n threshold scheme comput graph 26 5 2002 765 the given secret image is shared and n shadow images are thus generated each shadow image is hidden in an ordinary image so as not to attract an attacker s attention any t of the n hidden shadows can be used to recover the secret image the size of each stego image in which a shadow image is hidden is about 1 t of that of the secret image avoiding the need for much storage space and transmission time in the sense that the total size of t stego images is about the size of the secret image experimental results indicate that the qualities of both the recovered secret image and the stego images that contain the hidden shadows are acceptable the photographers who work in enemy areas can use this system to transmit photographs

a new t n multi secret sharing scheme based on shamir s secret sharing in 2000 chien et al proposed a t n multi secret sharing scheme at least t of the n participants can easily reconstruct p secrets at the same time but the secret reconstruction needs to solve simultaneous equations which is a complex process in order to reduce the complexity of the secret reconstruction yang et al proposed an alternative scheme based on shamir s secret sharing in 2004 but there are more public values required in yang s scheme than in chien s scheme when p

steganalysis of lsb matching based on statistical modeling of pixel difference distributions this paper presents a least significant bit lsb matching steganography detection method based on statistical modeling of pixel difference distributions previous research indicates that natural images are highly correlated in a local neighborhood and that the value zero appears most frequently in intensity differences between adjacent pixels the statistical model of the distribution of pixel difference can be established using the laplace distribution lsb matching steganography randomly increases or decreases the pixel value by 1 when the message is embedded thus the frequency of occurrence of the value zero in pixel differences changes most dramatically during message embedding based on the laplacian model of pixel difference distributions this paper proposes a method to estimate the number of the zero difference value using the number of non zero difference values from stego images and uses the relative estimation error between the estimated and actual values of the number of the zero difference value as the classification feature experimental results indicate that the proposed algorithm is effective in detecting lsb matching steganography and can achieve better detection performance than the local extreme method under most circumstances

phase transitions in an elementary probabilistic cellular automaton with memory abstract standard cellular automata ca are ahistoric memoryless i e the new state of a cell depends on the neighborhood configuration only at the preceding time step this article considers an extension to the standard framework of ca by implementing memory capabilities in cells thus in ca with memory while the update rules of the ca remain unaltered historic memory of all past iterations is retained by featuring each cell by a summary of all its past states a study is conducted of the effect of historic memory on a given side of the hypercube of elementary probabilistic ca which shows interesting phase transition phenomena

a verifiable multi secret sharing scheme based on cellular automata in this paper we propose a verifiable t n threshold multi secret sharing scheme based on one dimensional cellular automata where the number of secrets is not restricted by n or t we show that our scheme can be used to solve an open problem proposed recently in alvarez et al 2008 g alvarez l hernandez encinas a martin del rey a multisecret sharing scheme for color images based on cellular automata information sciences 178 2008 4382 4395

the restaurant at the end of the random walk recent developments in the description of anomalous transport by fractional dynamics fractional dynamics has experienced a firm upswing during the past few years having been forged into a mature framework in the theory of stochastic processes a large number of research papers developing fractional dynamics further or applying it to various systems have appeared since our first review article on the fractional fokker planck equation metzler r and klafter j 2000a phys rep 339 1 77 it therefore appears timely to put these new works in a cohesive perspective in this review we cover both the theoretical modelling of sub and superdiffusive processes placing emphasis on superdiffusion and the discussion of applications such as the correct formulation of boundary value problems to obtain the first passage time density function we also discuss extensively the occurrence of anomalous dynamics in various fields ranging from nanoscale over biological to geophysical and environmental systems

steganography of capacity required using modulo operator for embedding secret image in this paper a novel mechanism using modulus operations to incorporate secret data with image form into a host image is proposed the used modulus is a threshold value that indicates how many bits of the secret image are being incorporated into the host image in our scheme there are two kinds of secret images processed the capacities of these two types are half the size and a quarter the size of the chosen host image respectively as can be seen in the result of our experiment not only can the secret images be totally embedded but the extra information such as the auxiliary table assisting the secret extraction is released as well even then there is still space remaining after the hiding procedure is completed the result is a higher capacity exploration for embedding the secret into a host image upon inspection of the quality of the stego image using the measurement of psnr it is noted that not only does the image display make the grade of the human vision system i e it is imperceptible by human eyes as far as the embedded secret is concerned but also the valued results of psnr remain sufficiently stable for a variety of host image selections therefore our proposal scheme is notably superior to those in the previous literature iee proc vision image signal process 147 1 2000 29 the advantages of this proposed scheme are the higher capacity exploration on secret embedding and better stability on stego image displays

distributive weighted threshold secret sharing schemes the concept of distributive weighted threshold access structure is introduced which is an weighted threshold access structure where the participants are distributed on levels the participants on the same level are assigned the same weight and the threshold of the access structure is 1 the weight of the participants on the ith level is of the form 1 ki and therefore the ith level induces a standard threshold access structure with threshold ki we propose a crt based realization of distributive weighted threshold access structures which is asymptotically perfect and perfect zero knowledge we also show that distributive weighted threshold access structures do not generally have ideal realizations in case of just one level our scheme can be viewed as an asymptotically perfect and perfect zero knowledge variation of the asmuth bloom secret sharing scheme

image hiding by optimal lsb substitution and genetic algorithm in this paper we develop a novel method to embed important data in the host image so that the interceptors will not notice about the existence of the data the basic concept of the proposed method is by simple lsb substitution to prevent illicit access of data and increase the system performance the method of randomized process and the optimal lsb substitution are proposed the e ectiveness of the optimal lsb substitution in the worst case is proved we also develop a genetic algorithm to solve the problem of hiding important data in the rightmost k lsbs of the host image which may involve a huge computation time to nd the optimal result when k is large finally based on the concept of perceptual modeling an improved hiding technique is developed to obtain a high quality embedding result experimental results will reveal that the quality of the embedding result will not be seriously degraded and is near optimal by utilizing the proposed method 2001 pattern recognition society published by elsevier science ltd all rights reserved

an intelligent chaotic embedding approach to enhance stego image quality steganography s role in secret communication extends from concealing information to communication as one of several possible approaches to embed confidential information in digital images the least significant bit lsb technique has been widely used however maintaining the imperceptibility of the stego image is still a serious concern in this paper an adaptive random ar k bit embedding approach has been attempted to enhance the quality of stego images the original cover is divided into nonoverlapping blocks of equal size the encrypted confidential data are embedded in each block through four different random walks the best random walk which provides the minimum degradation for a particular block is identified and is fixed for that block the decision on the fixed random walk for each block is recorded and kept as the secret key the ar method has also been combined with the inverted pattern approach referred to as the adaptive random inverted pattern arip approach to further enhance the quality of the stego image the estimated peak signal to noise ratio psnr value for the arip method yields 1db enhancement

levy flights non local search and simulated annealing we solve a problem of non convex stochastic optimisation with help of simulated annealing of levy flights of a variable stability index the search of the ground state of an unknown potential is non local due to big jumps of the levy flights process the convergence to the ground state is fast due to a polynomial decrease rate of the temperature