ALBERT

Description: This paper discusses iterative identification problems for a class of output nonlinear systems (i.e., Wiener nonlinear systems) with moving average noises from input–output measurement data, based on the Newton iterative method. The basic idea is to decompose a nonlinear system into two subsystems, to replace the unknown variables in the information vectors with their corresponding estimates at the previous iteration, and to present a Newton iterative identification method using the hierarchical identification principle. The numerical simulation results indicate that the proposed algorithms are effective.

Description: The theory of chaos is applied to the construction of substitution boxes used in encryption applications. The synthesis process of the proposed substitution boxes is presented, which is based on chaotic Baker’s map and TDERC chaotic sequences. The objectives of the new substitution box are to provide enhanced resistance against differential and linear cryptanalysis. The constructed substitution boxes uses Galois field elements and relies on discrete chaotic maps while keeping differential and linear approximation probabilities to desired levels.

Description: We say that a noncooperative game is nonmonetized if the ranges of the utilities of theplayers are posets. In this paper, we examine some nonmonetized noncooperative games that bothof the collection of strategies and the ranges of the utilities for the players are posets. Then we carry theconcept of generalized Nash equilibriums of noncooperative games defined in [16, 17] to extended Nashequilibriums of nonmonetized noncooperative games. By applying some fixed point theorems in posetsand by using the order preserving property of mappings, we prove an existence theorem of extended Nashequilibriums for nonmonetized noncooperative games.

Description: An efficient fractal method based on discrete wavelet transfer is proposed in this paper. Before encoding, images with one-level wavelet transform are first partitioned into four subbands, which classify the range blocks as four types. An accelerated fractal coding method called variance sorting (VS) scheme with high reconstructed quality is addressed for the low-frequency components. Hereafter, the low-frequency part rebuilt performs one-level wavelet decomposition once again. The first-level high-frequency subbands excluding the diagonal directions are predicted according to the next coarser frequency scale in the same directions. Simulation experimental results compared with other classification algorithms demonstrate that the proposed method can obtain high compression ratio and reduce the encoding time without significant loss in the reconstructed image quality.

Description: This study presents a rule-based cooperative differential evolution (RCDE) learning algorithm to optimize the parameters of a compensatory neural fuzzy network (CNFN) for solving control problems. CNFN uses the compensatory degree for fuzzy reasoning to dynamically adjust fuzzy operators that can make the fuzzy system more adaptive and effective. RCDE decomposes the fuzzy system into multiple rule-based subpopulations where each subpopulation represents a fuzzy rule set, and each individual within each subpopulation evolves by differential evolution (DE) separately. The proposed RCDE uses cooperative behavior among multiple subpopulations for combining their information and building the complete fuzzy system to accelerate the search and increase global search capacity. Finally, the experimental results show that the proposed RCDE method better approximates the global optimal solution and has a faster convergence rate than the other methods.

Description: Traditionally, elastomers are considered to be one of the best material candidates for the design of energy absorbing devices, due to their remarkable visco-elastic and extensibility material properties. This capability can be further enhanced by the design of appropriate Dielectric Elastomer Generators (DEGs). The present paper proceeds to another alternative direction, which consists of the design of appropriate elastomer structures with enhanced energy absorption capabilities, are attributed more to the appropriate non-linear design of the elastomer structure itself, than to the hyperelastic material properties of the elastomer members. For this reason, a simple chi-shaped in-plane elastic structure is considered, comprising one proof mass with four elastomer members attached to it, placed in a chi-shaped configuration, and being properly stretched. A systematic analysis is carried out, with respect to the variation of two basic structure design properties on the dynamic behavior: the orientation angle of the members and their initial pre-stress. The obtained results show that the variation of just these two basic parameters of the structure may lead to a quite rich and interesting non-linear dynamic behavior. More specifically, the traditional always-in-tension concept leads to a linear dynamic system response, even though the elastomer members are considered to have been made of a non-linear hyper-elastic material. Alternatively, a new partially-loose-member operating concept is analyzed. This concept suggests that some individual elastomer members be allowed to become loose for some period of the operating cycle, (but not all of them simultaneously), strongly enhancing the broadband energy absorbing capability of the structure itself.

Description: The problem of sampled-data control is investigated for Takagi–Sugeno (T–S) fuzzy systems with aperiodic sampling intervals based on an enhanced input-delay approach. Delay-dependent stability and stabilizability conditions for the closed-loop continuous nonuniformly sampled-data fuzzy systems are derived by constructing a novel discontinuous Lyapunov–Krasovskii (L–K) functional, which makes good use of not only the upper bound on the variable sampling interval, but also its sawtooth structure information about varying input delay often ignored in previous results. A bounding technique combined by reciprocally convex technics and linear convex combination is presented for acquiring the time derivative of the functional, wherein Jensen’s inequality and Wirtinger’s inequality are integratively employed. And a feasible solution of the obtained criterion formulated as parameterized linear matrix inequalities is ultimately conceived. A numerical example is given to show the effectiveness of the proposed method.

Description: We introduce an iterative process which converges strongly to the common fixed point of a family of Lipschitzian pseudocontractive mappings. Our theorems improve and unify most of the results that have been proved forthis important class of nonlinear operators.

Description: n this paper, we introduce three iterative methods for finding a common elementof the set of fixed points for a continuous pseudo-contractive mapping and thesolution set of a variational inequality problem governed by continuous monotone mappings. Strongconvergence theorems for the proposed iterative methods are proved. Our resultsimprove and extend some recent results in the literature.

Description: Iterative schemas are ubiquitous in the area of abstract nonlinear analysis and still remain as a main tool for approximation of fixed points of generalizations of nonexpansive maps. The analysis of general iterative schemas, in a more general setup, is a problem of interest in theoretical numerical analysis. Therefore, we propose and analyze a general iterative schema for two finite families of asymptotically quasi-nonexpansive maps in hyperbolic spaces. Results concerning △-convergence as well as strong convergence of the proposed iteration are proved. It is instructive to compare the proposed general iteration schema and the consequent convergence results with that of several recent results in CAT(0) spaces and uniformly convex Banach spaces.MSC: 47H09, 47H10, 49M05.