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Offset boosting is a crucial passage for chaotic signal modification in chaos-based engineering. Searching an offset controller for a 3D chaotic system is usually complex, let alone two independent nonbifurcating offset constants. This paper constructs a class of chaotic systems, providing a single constant posing direct offset boosting for two dimensions. This offset boostable chaotic system regime has multiple typical control modes, including a system variable single control, synchronous common control, reverse control, and differential control. This new type of chaotic systems also finds two-dimensional offset boosting combined with amplitude control. [ABSTRACT FROM AUTHOR]

As a novel intelligent algorithm, fireworks algorithm (FWA) is applied to deal with different types of optimization problems. Since FWA's search processes are relatively simple, it is inefficient. In this paper, a dynamic multi-swarm competitive fireworks algorithm (DMCFWA) is developed to enhance the search capability of FWA. Firstly, based on the scaling coefficient updated by utilizing the fitness value of the optimal firework, the dynamic explosion amplitude strategy is proposed to improve the search capability of the best firework. Secondly, utilizing the location information of the fireworks, an improved search method is designed to enhance the local search capability of firework swarms. Thirdly, a multi-swarm independent selection technique and a restart operation are adopted to boost its abilities of global exploration and local exploitation. Finally, to reduce the computational cost of FWA, a new initialization method is used and a new model for calculating the spark number is embedded in DMCFWA. By adopting these strategies, DMCFWA easily implements and does well in exploitation and exploration. CEC2017 test suite and four engineering constraint problems are used to demonstrate the performance of DMCFWA. Experimental results show that DMCFWA performs more effectively and stably than its competitors. [ABSTRACT FROM AUTHOR]

This paper aims to present the exact closed-form solutions for the free vibration of double-beam systems composed of two parallel beams connected by an arbitrary number of discrete elastic supports. The general solutions of the mode shapes of the double-beam system are derived employing the Laplace transform method from a perspective of the entire domain of beams without enforcement of any segmentation. A unified strategy applied to various boundary conditions is proposed to determine the independent constants involved in the general solutions, as well as the frequency equation. Numerical calculations are performed to verify the present solutions by comparing the results from the previous literature and finite element simulation, and to discuss the effects of support parameters (stiffness, location, and number) on the modal characteristics of the double-beam system in detail. Outcomes show that the support location plays a pivotal role in regulating the modal characteristics of the double-beam system; for each-order mode, there are one or more potential optimal positions to maximize the effect of the elastic support. The mode veering phenomenon is detected as the support parameters change. It is highlighted that, by introducing an amplitude similarity index, the proximity degree for the mode shapes of the two beams influenced by the support parameters can be evaluated quantitatively. The present analysis is greatly helpful to the optimal design, health monitoring, and vibration control of the double-beam system. [ABSTRACT FROM AUTHOR]

The assembled tube-gusset K-joint by bolts is a commonly used connection form in steel tubular transmission towers. At present, main existing research or design codes for steel tubular transmission towers regard this K-joint as either rigid or pinned connections, which do not consider the semi-rigid behavior of K-joint. In this paper, the semi-rigid behavior of K-joint in steel tubular transmission towers is investigated and a direct prediction (DP) method is proposed to evaluate the semi-rigid behavior of K-joints based on the support vector regression (SVR) model, especially to predict the moment–rotation curve of semi-rigid K-joints. First, the establishment and validation of the finite element (FE) model of semi-rigid K-joints are conducted. Second, a dataset of 144 samples generated by the FE model is used to train and test the SVR model. Finally, the accuracy assessment of the proposed DP method and comparison with other existing methods, including the Kishi–Chen model, EC3 model and ANN-based two-step prediction method, are presented. The accuracy assessment shows that predicted values of the proposed DP method based on the SVR model exhibit good agreement with the numerical analysis values, which indicates the quite high accuracy of this method. Additionally, the comparison reveals that the proposed DP method based on the SVR model for predicting moment–rotation curves is rather more accurate than other aforementioned methods. Therefore, the proposed DP method based on the SVR model is of high reliability in predicting the semi-rigid behavior of K-joints in steel tubular transmission towers, which affords an alternative way for further engineering analysis and initial design purposes. [ABSTRACT FROM AUTHOR]

The time-varying mean (TVM) component plays a vital role in the characterization of non-stationary winds, whereas it is difficult to extract the TVM accurately or to validate it quantitively. To deal with this problem, this paper first develops two additional conditions for the TVM extraction from the perspective of structural wind-induced vibration response, then presents an approach, based on the combination of Vondrak filter and genetic algorithm (Vondrak-G), to derive the optimal TVM from non-stationary wind speed records as well as its turbulence characteristics (i.e. gust factor, turbulence intensity, and turbulence integral length scale). Furthermore, the wind characteristics obtained by the Vondrak-G approach are compared with those by a conventional approach derived for stationary winds, demonstrating that the results by the Vondrak-G approach are evidently more accurate. This paper aims to provide an effective method for accurately extracting the TVM and then evaluating wind characteristics of the non-stationary wind. [ABSTRACT FROM AUTHOR]

In this paper, we prove the existence of twelve small (local) limit cycles in a planar system with third-degree polynomial functions. The best result so far in literature for a cubic order planar system is eleven limit cycles. The system considered in this paper has a saddle point at the origin and two focus points which are symmetric about the origin. This system was studied by the authors and shown to exhibit ten small limit cycles: five around each of the focus points. It will be proved in this paper that the system can have twelve small limit cycles. The major tasks involved in the proof are to compute the focus values and solve coupled enormous large polynomial equations. A computationally efficient perturbation technique based on multiple scales is employed to calculate the focus values. Moreover, the focus values are perturbed to show that the system can exactly have twelve small limit cycles. [ABSTRACT FROM AUTHOR]

In spite of rapid evolution of electronic techniques, a number of large-scale applications continue to rely on the use of paper as the dominant medium. This is especially true for processing of bank checks. This paper examines the issue of reading the numerical amount field. In the case of checks, the segmentation of unconstrained strings into individual digits is a challenging task because of connected and overlapping digits, broken digits, and digits that are physically connected to pieces of strokes from neighboring digits. The proposed architecture involves four stages: segmentation of the string into individual digits, normalization, recognition of each character using a neural network classifier, and syntactic verification. Overall, this paper highlights the importance of employing a hybrid architecture that incorporates multiple approaches to provide high recognition rates. [ABSTRACT FROM AUTHOR]

In this paper, a symbolic dynamical model of the average queue size of the random early detection (RED) algorithm is proposed. The conditions for both the system parameters and the initial conditions that the average queue size of the RED algorithm would converge to a fixed point are derived. These results are useful for network engineers to design both the system parameters and the initial conditions so that internet networks can achieve a good performance. [ABSTRACT FROM AUTHOR]

This paper studies the mechanisms of ionic channels in neurons of lamprey central pattern generator (CPG), such as the N-methyl-D-aspartate (NMDA) receptor channel and the calcium-dependent potassium channel etc. The CPG properties on oscillation attributed to the ionic mechanisms are exploited. The conditions for oscillation, divergence, convergence and the guidelines on selection of the parameters are established. The effects of key parameters on CPG frequency and duty cycle are investigated. Mathematical analysis and simulation study is performed to verify these results. This study will potentially enhance the effective application of biological CPG model into engineering practice such as robotics. [ABSTRACT FROM AUTHOR]

An efficient method to eliminate redundant frequencies present in one of the existing multi-frequency methods for analog fault diagnosis is proposed in this paper. First the two-dimensional fault dictionary is constructed where entries are gain signatures of all faults and frequencies. The faults belonging to the same quantization levels are numbered sequentially and a frequency that has an ambiguity set with the highest number faults is eliminated after verifying that there are no repetitions after the deletion of this frequency. In this manner, all frequencies are examined for deletion. Finally the test frequencies, which cannot be deleted, remain resulting in a minimal set of test frequencies of a network to isolate a given set of faults. Another method proposes a technique, which generates more number of frequencies to isolate all the faults, if the test frequencies generated using the existing methods are not sufficient. [ABSTRACT FROM AUTHOR]

In this paper, we present an adaptive circuit design that is capable of increasing the effective size-ratio of combinational logic gates to extend the balanced operation in the subthreshold region as well as to maintain high performance at the nominal VDD. We optimize the sizes of the PMOS transistors in the pull-up network for minimum power dissipation and propagation delay over a wide range of supply voltage. In addition to the minimized energy operation, the dynamically adjustable gate size-ratio allows the gate to preserve a symmetric voltage transfer characteristic at both normal supply and subthreshold operation, which translates to maximized noise margins. Simulation results show that up to 70.9% reduction in the energy can be achieved for a ring oscillator, as compared to the fixed size design capable of operating under supply voltage in the range of 75 mV to 1.2 V. For designs working under dynamic voltage scaling schemes, our technique presents a very effective and efficient solution for balanced minimum energy operation in the subthreshold region while preserving high performance at the nominal supply voltage. [ABSTRACT FROM AUTHOR]

Error correcting codes (ECCs) are commonly used as a protection against the soft errors. Single error correcting and double error detecting (SEC–DED) codes are generally used for this purpose. Such circuits are widely used in industry in all types of memory, including caches and embedded memory. In this paper, a new genetic design for ECC is proposed to perform SEC–DED in the memory check circuit. The design is aimed at finding the implementation of ECC which consumes minimal power. We formulate the ECC design into a permutable optimization problem and employ special genetic operators appropriate for this formulation. Experiments are performed to demonstrate the performance of the proposed method. [ABSTRACT FROM AUTHOR]

In this paper, a new frame rate up-conversion (FRC) using Backward Multiple Reference Frame Motion (BMRF) compensated interpolation (MCI) algorithm is proposed. The BMRF algorithm has been compared with two most common MCI methods, Temporal Linear (TLIN) and Bidirectional MCI (BID) used in FRC, in the aspect of PSNR, perceptual quality, and computational complexity. The simulation results clearly showed that BMRF presented a trade-off solution between computation and interpolation quality. By using simple weighted frame interpolation between multiple frames, it reduced computation rapidly while keeping similar interpolation quality when compared to the BID method. The simplicity of the BMRF algorithm made it suitable for either software or hardware implementation essential for real-time FRC applications. [ABSTRACT FROM AUTHOR]

In this paper, a lattice ℓ-step ahead output uncertainty prediction algorithm is presented. The proposed prediction scheme is applicable to linear, stable, auto-regressive (AR) systems. The uncertainty predictors utilize the structure of the lattice filters. Subject to the saturation limits of the excitation signal, the measurement of the system output, and the a priori bounds of the reflection coefficients, the set of the feasible predicted output variables is computed. The suggested scheme is recursively computed over an ℓ-step ahead future time window, while the prediction uncertainty intervals are similarly computed over the lattice stages, regarding the forward and the backward prediction errors. Simulation results are presented that prove the efficacy of the employed lattice uncertainty predictors. [ABSTRACT FROM AUTHOR]

In the tolerance analysis of electronic circuits, the concept of set-valued function is often useful. In this paper, an efficient algorithm is proposed for finding all solution sets of nonlinear resistive circuits described by systems of nonlinear equations containing set-valued functions termed piecewise-trapezoidal (PWT) functions. By numerical examples, the effectiveness of the proposed algorithm is confirmed from various viewpoints. It is also shown that the proposed algorithm could find all solution regions to a system of 1000 PWT equations in practical computation time. [ABSTRACT FROM AUTHOR]

In this paper we examine the localization problem of compact invariant sets of nonlinear time-varying systems with the differentiable right-side. We extend our results respecting the localization problem obtained earlier for time-invariant systems and apply them to a damped driven pendulum and the Vallis model with regard to the seasonal cycle. [ABSTRACT FROM AUTHOR]

The aim of this paper is to present and analyze a minimal chaotic map of the plane, then we describe in detail the dynamical behavior of this map, along with some other dynamical phenomena. [ABSTRACT FROM AUTHOR]

In this paper, we propose an object selective attention and perception system, which was implemented by integrating a specific object preferable attention model with an incremental object perception model. The object oriented attention model can selectively pay attention to the candidates of an object in natural scenes based on a bottom-up selective attention model in conjunction with a top-down biased attention mechanism for a specific object. A generative model based on an incremental Bayesian parameter estimation is considered in order to perceive arbitrary objects in the attended areas. Combining an object oriented attention model with general object perception model, the developed system cannot only pay attention to a specific target object but can also memorize the characteristics of task nonspecific objects in an incremental manner. Experimental results show that the developed system generates good performance in successfully focusing on the target objects as well as incrementally perceiving objects in natural scenes. [ABSTRACT FROM AUTHOR]

This paper investigates different types of chaotic synchronization in a system of two coupled sine maps. Due to the bimodal nature of the individual map, there is a range of parameters in which two synchronized chaotic states coexist along the main diagonal. In certain parameter regions, various (regular or chaotic) asynchronous states coexist with the synchronized chaotic states, and the basins of attraction become quite complicated. We determine the regions of stability for the so-called principal cycles that arise through transverse period-doubling bifurcations of synchronized saddle cycles. Particular emphasis is paid to the occurrence of chaotic antisynchronization, the coexistence of antisynchronous chaotic states, and the presence of narrow regions of parameter space in which states of chaotic synchronization and antisynchronization exist simultaneously. For each of these cases we provide detailed pictures of the associated basin structures. [ABSTRACT FROM AUTHOR]

This paper proposes a symbolic reachability analysis method for multiple-clock system design, which is the first approach to deal with both synchronization problems caused by metastability and rate mismatch problems caused by clock frequency mismatches in a single framework. Three methods are described to reproduce problems that occur with multiple-clock system design during reachability analysis: (1) alternate evaluation for a system with two clocks as the base-line model, (2) nondeterministic delayed evaluation to reproduce a synchronization problem, and (3) double evaluation to reproduce a clock frequency mismatch. Experimental results on ISCAS 89 benchmark show an improvement factor of average CPU time as compared to Clarke's method by 1.29, 55.41, 2.19 and 45.23 times when alternate evaluation, double evaluation, alternate evaluation with NDDE and double evaluation with NDDE is applied, respectively. [ABSTRACT FROM AUTHOR]

By analyzing the dynamic behaviors of the transiently chaotic neural network and greedy heuristic for the maximum independent set (MIS) problem, we present an improved transiently chaotic neural network for the MIS problem in this paper. Extensive simulations are performed and the results show that this proposed transiently chaotic neural network can yield better solutions to p-random graphs than other existing algorithms. The efficiency of the new model is also confirmed by the results on the complement graphs of some DIMACS clique instances in the second DIMACS challenge. Moreover, the improved model uses fewer steps to converge to stable state in comparison with the original transiently chaotic neural network. [ABSTRACT FROM AUTHOR]

In this paper, an approach based on ergodic properties for classifying chaotic sequences is given. It is particularly robust due to the open-loop structure of the detector. Unlike previous works in this direction, such as those concerning the inverse system approach, the detector is not uniquely determined by the transmitter (identical or subsystem thereof), but instead depends on the measurement noise model. The classification is optimized under such imperfect observation conditions. The method is introduced in general for the case of chaotic sequences generated by ergodic maps, and a special case is analyzed in detail to illustrate the method. This special example resorts to Tchebychev maps and some additional symmetries to make up a simple signaling scheme which is low in complexity on both transmitter and receiver sides, while at the same time relatively robust, due to the open-loop structure of the detector. [ABSTRACT FROM AUTHOR]

There is an important interest in compensating thermally induced errors of modular tool systems to improve the manufacturing accuracy. In this paper, we test the hypothesis whether we can predict such thermal displacements by using a nonlinear regression analysis, namely the alternating conditional expectation algorithm (ACE [Breiman & Friedman, 1985]), reliably. The data analyzed were generated by two different finite element spindle models of modular tool systems. As the main result, we find that the ACE-algorithm is a powerful tool to model the relation between temperatures and displacements. The maximal correlation is larger than 0.999 in both cases, which demonstrates the suitability of the ACE algorithm. Furthermore, preconditions for the applicability of this approach, such as the length and the support of measured data sets, are studied. Hence, this approach seems to be promising for the application to real modular tool systems. [ABSTRACT FROM AUTHOR]

A polygonal approximation captures the essential features of a digital planar curve and yields a compact representation. Those points of the digital curve that carry vital information about the shape of the curve form the vertices of the approximating polygon and are called significant vertices. In this paper, we present a genetic algorithm-based approach to locate a specified number of significant points, such that the approximation error between the original curve and its polygonal version obtained by joining the adjacent significant points is minimized. By using a priori knowledge about the shape of the curve we confine our search to only those points of the curve that have the potential of qualifying as significant points. We also incorporate chromosome differentiation to improve upon the effectiveness of the search in arriving at a near-optimal polygonal approximation. Finally, we show that the proposed method performs remarkably well when evaluated in terms of the metrics available for assessing the goodness of a polygonal approximation algorithm. [ABSTRACT FROM AUTHOR]

In this paper, we present a new approach to geometrical modeling which allows the user to easily characterize and control the shape defined to a closed surface. We will focus on dealing with the shape's topological, morphological and geometrical properties separately. To do this, we have based our work on the following observations concerning surfaces defined by control-points, and implicit surfaces with skeleton. They both provide complementary approaches to the surface's deformation, and both have specific advantages and limits. We thus attempted to conceive a model which integrates the local and geometrical characterization induced by the control points, as well as the representation of the morphology given by the skeleton. Knowing that the lattice of control points is close to the surface and that the skeleton is centered in the related shape, we thought of a 3-layer model. The transition layer separates the local geometrical considerations from those linked to the global morphology. We apply our model to shape design in order to modify an object in an interactive and ergonomic way, as well as to reconstruction which allows better shape understanding. To do so, we present the algorithms related to these processes. [ABSTRACT FROM AUTHOR]

To investigate the geometrically nonlinear behavior of space structures using finite elements, the total Lagrangian (TL), updated Lagrangian (UL) and co-rotational (CR) procedures have been used by researchers. For 3D truss structures, the CR formulation has been reported to be computationally more efficient as it possesses the rigid body displacement components during deformations. In this paper, the secant stiffness matrix of truss element will be derived using a simple co-rotational, total Lagrangian (CR–TL) formulation. The incremental rotation matrix, which is the pivotal quantity in the CR formulation, is derived from geometric principles. The secant stiffness matrix is presented in terms of the natural degrees-of-freedom of the truss element. The efficiency and reliability of the present formulation is demonstrated in the solution of several truss problems involving the postbuckling behavior. [ABSTRACT FROM AUTHOR]

This paper presents a chaotic oscillator based on the nonlinearity of the typical transconductance (Gm). This chaotic circuit only consists of 13 MOS transistors and three grounded capacitors, which is one of the smallest chaotic oscillators. This circuit operates on low voltage supply (±1.5 V). The dimensionless form of the circuit is also introduced to confirm the circuit simulation. [ABSTRACT FROM AUTHOR]

The article reports that the cover story in a 2008 issue of "Pharma Focus Asia" featured associate professor Lim Chwee Teck from the Department of Mechanical Engineering and Division of Bioengineering at the National University of Singapore (NUS). Lim was the first to conduct mechanobiology research on human diseases at cellular and molecular levels. Aside from setting up the Nano Biomechanics Lab in 2002, he also published highly-cited papers in both engineering and biology related journals and won various research awards.

This section is maintained by Vladik Kreinovich. Please send your abstracts (or copies of papers that you want to see reviewed here) to vladik@utep.edu, or by regular mail to: V. Kreinovich, Department of Computer Science, University of Texas, El Paso, TX 79968, USA. [ABSTRACT FROM AUTHOR]