Derivation of Error Distribution in Least Squares Steganalysis

This paper considers the least squares method (LSM) for estimation of the length of payload embedded by least-significant bit replacement in digital images. Errors in this estimate have already been investigated empirically, showing a slight negative bias and substantially heavy tails (extreme outliers). In this paper, (approximations for) the estimator distribution over cover images are derived: this requires analysis of the cover image assumption of the LSM algorithm and a new model for cover images which quantifies deviations from this assumption. The theory explains both the heavy tails and the negative bias in terms of cover-specific observable properties, and suggests improved detectors. It also allows the steganalyst to compute precisely, for the first time, a p-value for testing the hypothesis that a hidden payload is present. This is the first derivation of steganalysis estimator performance     

On the stability issues of linear Takagi-Sugeno fuzzy models

Stability issues of linear Takagi-Sugeno (TS) fuzzy models (1985, 1992) are investigated. We first propose a systematic way of searching for a common matrix, which, in turn, is related to stability for N subsystems that are under a pairwise commutative assumption. The robustness issue under uncertainty in each subsystem is then considered. We then show that the pairwise commutative assumption can, in fact, be relaxed by a similar approach as that for uncertainty. The result is applicable to a rather broad class of TS models, which are nonHurwitz and/or nonpairwise commutative     

Functions of orthogonal projectors involving the Moore–Penrose inverse

Several results scattered in the literature express an oblique projector having given onto and along spaces in terms of a pair of orthogonal projectors. The results were established in various settings, including finite and infinite dimensional vector spaces over either real or complex numbers, but their common feature is that they are valid merely under the assumption of the nonsingularity of certain functions of the involved projectors. In the present paper, these results are unified and reestablished in a generalized form in a complex Euclidean vector space, with the generalization obtained by relaxing the nonsingularity assumption and use of the Moore–Penrose inverse instead of the ordinary inverse. Additionally, several new formulae of the type are provided.     

基于三次剩余的新Paillier签名方案

针对基于二次剩余Paillier数字签名方案标签设置过程和签名过程比较复杂等问题,提出了一个基于三次剩余的新Paillier数字签名方案。分析结果表明所提出的方案在计算效率上优于已有的签名方案。在大整数难以分解的假设下,提出的签名方案可抵抗存在性伪造以及适应性选择消息攻击。     

Overcoming the detectability obstacle in certainty equivalence adaptive control

In this paper, we are interested in global adaptive stabilization of nonlinear systems where we know a linearly parametrized stabilizer and a Lyapunov function for the ideal closed-loop system such that the standard estimator is implementable, but this Lyapunov function is not strict, i.e., its derivative is only negative semi-definite. Our motivation to consider this situation stems from the fact that, for many physical systems, the natural Lyapunov function candidate is the total energy, which is always not strict. To complete the stability proof in this case it is necessary to add a—rather restrictive—detectability assumption. Our main contribution is to show that it is possible to overcome this obstacle by adding to the parameter estimator an identification error coming from an indirect identifier. We thus replace the detectability assumption by a new condition that essentially requires that the negative-definite terms appearing in the Lyapunov function derivative dominate, the uncertain terms that cannot be matched by the controller. No matching, or persistency of excitation assumptions are needed.     

An algebraic approach to shape-from-image problems

This paper presents a new method for recovering three-dimensional shapes of polyhedral objects from their single-view images. The problem of recovery is formulated in a constrained optimization problem, in which the constraints reflect the assumption that the scene is composed of polyhedral objects, and the objective function to be minimized is a weighted sum of quadric errors of surface information such as shading and texture. For practical purpose it is decomposed into the two more tractable problems: a linear programming problem and an unconstrained optimization problem. In the present method the global constraints placed by the polyhedron assumption are represented in terms of linear algebra, whereas similar constraints have usually been represented in terms of a gradient space. Moreover, superstrictness of the constraints can be circumvented by a new concept ‘position-free incidence structure’. For this reason the present method has several advantages: it can recover the polyhedral shape even if image data are incorrect due to vertex-position errors, it can deal with perspective projection as well as orthographic projection, the number of variables in the optimization problem is very small (three or a little greater than three), and any kinds of surface information can be incorporated in a unifying manner.     

Multigrid Methods for Hellan–Herrmann–Johnson Mixed Method of Kirchhoff Plate Bending Problems

A V-cycle multigrid method for the Hellan–Herrmann–Johnson (HHJ) discretization of the Kirchhoff plate bending problems is developed in this paper. It is shown that the contraction number of the V-cycle multigrid HHJ mixed method is bounded away from one uniformly with respect to the mesh size. The uniform convergence is achieved for the V-cycle multigrid method with only one smoothing step and without full elliptic regularity assumption. The key is a stable decomposition of the kernel space which is derived from an exact sequence of the HHJ mixed method, and the strengthened Cauchy Schwarz inequality. Some numerical experiments are provided to confirm the proposed V-cycle multigrid method. The exact sequences of the HHJ mixed method and the corresponding commutative diagram is of some interest independent of the current context.     

A new treatment for calculating activities from phase diagrams involving two liquid or solid coexisting phases

New formulae for calculating activities and activity coefficients from phase diagram at a fixed temperature are presented for a binary system involving a two liquid or solid coexisting phases. In the new formulae. Richardson's assumption that for many systems is approximately equal to 3000, has been adopted. In terms of the new formulae, activities of components in Zn-Pb and Zn-Bi binary systems are calculated and the results show that the formulae are efficient.     

A single-step procedure for estimating seismically-induced displacements in earth structures

Estimation of the permanent deformations of embankment dams is, in practice, based upon the simplifying assumption that dynamic-acceleration response and wedge sliding are two separate processes (decoupled ‘elastic’ and ‘rigid-slip’ features of the dynamic response). An alternative hypothesis is proposed in this paper, namely that these two processes occur simultaneously. To this end, the dam is assumed to contain an a priori assigned, potentially-sliding interface, and the dynamic response is computed in a single step. As a validation of the new single-step procedure, a numerical analysis is carried out and shown to successfully explain the asymmetric response of La Villita Dam recorded during the Mexico earthquake of 15 September, 1985. All analyses are performed with ADINA using special interface elements to model the slip and Newmark's time-integration algorithm for a direct step-by-step solution.     

Robust <Emphasis Type="Italic">H</Emphasis><Subscript>∞</Subscript> Performance of Discrete-time Neural Networks with Uncertainty and Time-varying Delay

In this paper, we are concerned with the robust H_∞ problem for a class of discrete-time neural networks with uncertainties. Under a weak assumption on the activation functional, some novel summation inequality techniques and using a new Lyapunov-Krasovskii (L-K) functional, a delay-dependent condition guaranteeing the robust asymptotically stability of the concerned neural networks is obtained in terms of a Linear Matrix Inequality(LMI). It is shown that this stability condition is less conservative than some previous ones in the literature. The controller gains can be derived by solving a set of LMIs. Finally, two numerical examples result are given to illustrate the effectiveness of the developed theoretical results.     

A probabilistic justification for using tf×idf term weighting in information retrieval

This paper presents a new probabilistic model of information retrieval. The most important modeling assumption made is that documents and queries are defined by an ordered sequence of single terms. This assumption is not made in well-known existing models of information retrieval, but is essential in the field of statistical natural language processing. Advances already made in statistical natural language processing will be used in this paper to formulate a probabilistic justification for using tf×idf term weighting. The paper shows that the new probabilistic interpretation of tf×idf term weighting might lead to better understanding of statistical ranking mechanisms, for example by explaining how they relate to coordination level ranking. A pilot experiment on the TREC collection shows that the linguistically motivated weighting algorithm outperforms the popular BM25 weighting algorithm. Received: 17 December 1998 / Revised: 31 May 1999     

A new exponentially weighted moving average sign chart using repetitive sampling

In this paper, a new nonparametric control chart based on the exponentially weighted moving average (EWMA) sign statistic is proposed using repetitive sampling. The control chart is proposed to effectively detect the process mean shift away from the target value without the distributional assumption on the quality characteristic. The proposed control chart is based on two pairs of upper and lower control limits having different control coefficients. The in-control and the out-of-control average run lengths of the proposed control chart are evaluated through the Monte Carlo simulation. The proposed control chart is shown to be more efficient than the existing EWMA sign control chart in terms of the average run length.     

A multi-product EOQ model with pricing consideration—T. C.E. Cheng''s momdel revisited

We present two major revisions/corrections regarding a recent paper by T.C.E. Cheng [Computers ind. Engng 18, 529–534 (1990)]. Firstly, we note that a critical assumption of equal replenishment cycle length for all products is stated, but not incorporated into the mathematical formulation in Cheng. In this paper, we re-formulate the problem with equal replenishment cycle length incorporated and derive the corresponding Kuhn-Tucker optimality conditions. Next, under linear demand assumption, we show that the closed-form solutions provided by Cheng may result in non-optimal solutions. The reason is that Cheng failed to derive conditions under which closed-form solutions may be optimal. In this paper, by employing trigonometric methods {see e.g. Chap. 2 of Griffiths [Introduction of the Theory of Equations. Wiley, New York (1945).] or Appendix of Porteus [Mgmt Sci. 31, 998–1010 (1985)]}, we derive an optimal closed-form solution that is unqiue and obtain conditions under which the optimal closed-form solution is valid.     

Mining team compositions for collaborative work in business processes

Process mining aims at discovering processes by extracting knowledge about their different perspectives from event logs. The resource perspective (or organisational perspective) deals, among others, with the assignment of resources to process activities. Mining in relation to this perspective aims to extract rules on resource assignments for the process activities. Prior research in this area is limited by the assumption that only one resource is responsible for each process activity, and hence, collaborative activities are disregarded. In this paper, we leverage this assumption by developing a process mining approach that is able to discover team compositions for collaborative process activities from event logs. We evaluate our novel mining approach in terms of computational performance and practical applicability.     

New delay-dependent stability results for discrete-time recurrent neural networks with time-varying delay

This paper studies the problem of stability analysis for discrete-time recurrent neural networks (DRNNs) with time-varying delays. By using the discrete Jensen inequality and the sector bound conditions, a new less conservative delay-dependent stability criterion is established in terms of linear matrix inequalities (LMIs) under a weak assumption on the activation functions. By using a delay decomposition method, a further improved stability criterion is also derived. It is shown that the newly obtained results are less conservative than the existing ones. Meanwhile, the computational complexity of the newly obtained stability conditions is reduced since less variables are involved. A numerical example is given to illustrate the effectiveness and the benefits of the proposed method.     

Comments, on `A generalization of Rosenbrock's theorem' by M.Schlegel

In the above paper (ibid., vol.AC-32, p.155, Feb. 1987) the author presents a generalization of the famous Rosenbrock theorem concerning the problem of synthesis of linear state feedback control laws for linear controllable systems. The commenters point out that this result was published by them earlier (in an alternative form). Here they give again alternative conditions for solvability of the problem, since the original papers (published in 1979 and 1985) were in Russian. In contrast to the conditions given in the above paper, their conditions are not redundant and are given in terms of order relation on the lattice of integer partitions     

Solipsism,individualism and cognitive science

Abstract

‘Artificial Intelligence cannot ignore philosophy’ (McCarthy 1988) I shall challenge the claim that good old-fashioned artificial intelligence, or GOFAI (Haugeland 1985) is solipsistic while more recent neural or ‘brain-style’ approaches to AI are not (Rumelhart et al. 1986). After distinguishing GOFAI from connectionism, I will first show that GOFAI is not committed to solipsism but rather to what is more properly called individualism. I argue that the feature of GOFAI which entails individualism is shared by connectionism. Individualism is a metaphysical assumption of both types of AI, one which may indeed be pernicious. It is an assumption which must be located and understood.     

Video-based, real-time multi-view stereo

We investigate the problem of obtaining a dense reconstruction in real-time, from a live video stream. In recent years, multi-view stereo (MVS) has received considerable attention and a number of methods have been proposed. However, most methods operate under the assumption of a relatively sparse set of still images as input and unlimited computation time. Video based MVS has received less attention despite the fact that video sequences offer significant benefits in terms of usability of MVS systems. In this paper we propose a novel video based MVS algorithm that is suitable for real-time, interactive 3d modeling with a hand-held camera. The key idea is a per-pixel, probabilistic depth estimation scheme that updates posterior depth distributions with every new frame. The current implementation is capable of updating 15 million distributions/s. We evaluate the proposed method against the state-of-the-art real-time MVS method and show improvement in terms of accuracy.