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For all humanity, the sudden outbreak of Corona Virus Disease 2019 has been an important problem. Timely and effective media coverage is considered to be one of the effective approaches to control the spread of epidemic in early stage. In this paper, a Sentiment‐enabled Susceptible‐Exposed‐Infected‐Recovered (SEIR) model is established to reveal the relationship between the propagation of the epidemic and media coverage. The authors take the positive and negative media coverage into consideration when implementing the Sentiment‐enabled SEIR model. This model is constructed by parameterizing the number of current confirmed cases, cumulative cured cases, cumulative deaths, and media coverage. The numerical simulation and sensitivity analysis are conducted based on the Sentiment‐enabled SEIR model. The numerical analysis confirms the rationality of the Sentiment‐enabled SEIR model. The sensitivity analysis shows that positive media coverage acts a pivotal part in reducing the figure for confirmed cases. Negative media coverage has an effect on the figure for confirmed cases is not as significant as that of positive media coverage, but it is not negligible. [ABSTRACT FROM AUTHOR]

The aim of this paper is to establish a precise illustration for the structure of the nonconstant steady states for a Beddington–DeAngelis and Tanner predator–prey reaction–diffusion system with prey‐taxis. We treat the nonlinear prey‐taxis as a bifurcation parameter to analyze the bifurcation structure of the system. Furthermore, the exported global bifurcation theorem, under a rather natural condition, offers the existence of nonconstant steady states. In the proof, a priori estimates of steady states will play an important role. The local stability analysis with a numerical simulation and bifurcation analysis are given. Finally, some conclusions including biological meanings are performed to summarize our main analytic results and future investigations. [ABSTRACT FROM AUTHOR]

In recent years, the finite-difference time-domain (FDTD) method has been used to simulate a wide range of frequency dependent media. The accuracy of these simulations often depends on how accurately the complex dielectric constant is simulated in the sampled time domain used by FDTD. This paper describes the process of modelling the complex dielectric constant as a digital filtering problem and uses Z transforms to convert the frequency domain expression to a sampled time domain expression. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A new approach using FIT-formulation (Finite Integration Technique) (T. Weiland, Electron. Commun., 31, 116–120 (1977); Int. J. Numer. Model., 9, 295–319 (1996)) for simulating waveguide propagation of optical pulses is presented. FIT-methods are widespread in use for broadband linear simulations. In recent years, several attempts have been made to describe different dispersive material-characteristics such as Drude, Debye or Lorentz dispersion. Today advanced FDTD-formulations (Finite Difference Time Domain) also consider non-linear effects (P. M. Goorjian and A. Taflove, IEEE Opt. Lett., 17(3), 180–182 (1992); D. M. Sullivan, IEEE Trans. Microwave Theory Techniques, 43(3), 676–682 (1995)). In the following presented method third-order non-linear effects were described, which can be observed in isotropic media in frequency ranges of optical pulses, by updating material polarization terms using classical descriptions of Lorentz dispersion, Raman scattering and the Kerr effect. The basic idea is transforming these description formulas into sets of linear differential equations and solving them with the help of the general exponential solution. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, a delayed mosquito population suppression model with stage and sex structure is constructed incorporating periodic releases of the sterile mosquito and its sexual lifespan. Sterile mosquitoes are released periodically into the field to suppress the wild mosquito population, and only sexually active sterile mosquitoes are included in the interaction system of these two populations. According to the relationship between the release period T$$ T $$ and the sexual lifespan T1$$ {T}_1 $$, we study the dynamic behaviors of the system, such as the existence of positive periodic solutions and the stability of extinction equilibrium in three cases. A series of numerical simulations are performed, which not only verify the reliability of the theoretical results but also make a numerical analysis of the open problems raised in the theoretical research. [ABSTRACT FROM AUTHOR]

This paper presents a novel perspective on fully distributed adaptive protocol design for bipartite consensus under directed communication graphs. It is revealed that the fully distributed protocol is indeed a PI‐gain design approach. Based on such PI‐gain method, fully distributed observer‐based protocols are proposed to solve the consensus problem of nonlinear multi‐agent systems over directed cooperative‐antagonistic networks, where the neural network approximation is introduced to tackle the unknown nonlinearity. Fully distributed continuous protocols are further presented by modifying the sign function with a decaying variable, which takes the advantage of avoiding chattering problem. Theoretical analysis and numerical simulations are given to support our main results. [ABSTRACT FROM AUTHOR]

Since the pioneering work of Turing, it has been known that diffusion can destablise a homogeneous solution that is stable in the underlying model in the absence of diffusion. The destabilisation of the homogeneous solutions leads to the generation of patterns. In recent years, techniques have been developed to analyse so‐called localised spatial structures. These are solutions in which the spatial structure occurs in a localised region. Unlike Turing patterns, they do not spread out across the whole domain. We investigate the existence of localised structures that occur in two predator‐prey models. The functionalities chosen have been widely used in the literature. The existence of localised spatial structures has not investigated previously. Indeed, it is easy to show that these models cannot exhibit the Turing instability. This has perhaps led earlier researchers to conclude that interesting spatial solutions can therefore not occur for these models. The novelty of our paper is that we show the existence of stationary localised patterns in systems which do not undergo the Turing instability. The mathematical tools used are a combination of Linear and weakly nonlinear analysis with supporting numerical methods. By combining these methods, we are able to identify conditions for a wide range of increasing exotic behaviour. This includes the Belyckov‐Devaney transition, a codimension two spatial instability point and the formation of localised patterns. The combination of spectral computations and numerical simulations reveals the crucial role played by the Hopf bifurcation in mediating the stability of localised spatial solutions. Finally, numerical solutions in two spatial dimensions confirms the onset of intricate spatio‐temporal patterns within the parameter regions identified within one spatial dimension. [ABSTRACT FROM AUTHOR]

Anomalous diffusion problems are used to describe the evolution of particle's motion in crowded environments with many applications, such as modeling the intracellular transport and disordered media. In the present paper, we develop a Petrov–Galerkin spectral method for the fourth‐order anomalous fractional diffusion equations. For the dimension reduction, we use a discretization in time by the convolution quadrature. We then introduce the basis sets for the trial‐and‐test spaces using modal Bernstein basis functions with a presentation of the method in a weak spectral formulation along with a discussion of the structure of the resulting systems, the convergence, and stability of the proposed method. The theoretical results are supported by illustrating some numerical examples. [ABSTRACT FROM AUTHOR]

In this paper, an efficient numerical procedure for the generalized nonlinear time‐fractional Klein–Gordon equation is presented. We make use of the typical finite difference schemes to approximate the Caputo time‐fractional derivative, while the spatial derivatives are discretized by means of the cubic trigonometric B‐splines. Stability and convergence analysis for the numerical scheme are discussed. We apply our scheme to some typical examples and compare the obtained results with the ones found by other numerical methods. The comparison shows that our scheme is quite accurate and can be applied successfully to a variety of problems of applied nature. [ABSTRACT FROM AUTHOR]

When experimental resources are significantly constrained, resolution V fractional factorial designs are often prohibitively large for experiments with 6 or more factors. Resolution IV designs may also be cost prohibitive, as additional experimentation may be required to de-alias active 2-factor interactions (2FI). This paper introduces 20-run no-confounding screening designs for 6 to 12 factors as alternatives to resolution IV designs. No-confounding designs have orthogonal main effects, and since no 2FI is completely confounded with another main effects or 2FI, the experimental results can be analyzed without follow-on experimentation. The paper concludes with the results of a Monte Carlo simulation used to assess the model-fitting accuracy of the recommended designs. [ABSTRACT FROM AUTHOR]

The three‐dimensional displacement of two‐phase flow in porous media is a preliminary problem of numerical simulation of energy science and mathematics. The mathematical model is formulated by a nonlinear system of partial differential equations to describe incompressible miscible case. The pressure is defined by an elliptic equation, and the concentration is defined by a convection‐dominated diffusion equation. The pressure generates Darcy velocity and controls the dynamic change of concentration. We adopt a conservative block‐centered scheme to approximate the pressure and Darcy velocity, and the accuracy of Darcy velocity is improved one order. We use a block‐centered upwind multistep method to solve the concentration, where the time derivative is approximated by multistep method, and the diffusion term and convection term are treated by a block‐centered scheme and an upwind scheme, respectively. The composite algorithm is effective to solve such a convection‐dominated problem, since numerical oscillation and dispersion are avoided and computational accuracy is improved. Block‐centered method is conservative, and the concentration and the adjoint function are computed simultaneously. This physical nature is important in numerical simulation of seepage fluid. Using the convergence theory and techniques of priori estimates, we derive optimal estimate error. Numerical experiments and data show the support and consistency of theoretical result. The argument in the present paper shows a powerful tool to solve the well‐known model problem. [ABSTRACT FROM AUTHOR]

The increase in extraction height will increase the mining‐induced overlying strata failure height. In this scenario, the strata pressure behavior is strong in a fully mechanized face with large mining height (FMFLMH), which frequently causes coal wall falls, roof falls, and hydraulic support failure accidents (e.g., support closure and hydraulic column damage). The key to solving these issues is to determine support's working resistance of the FMFLMH. In this paper, comprehensive theoretical analysis, numerical simulation, and field observation were applied to determine the support's working resistance in the FMFLMH based on movement type of the first subordinate key stratum (SKS 1). First, six kinds of movement types of SKS 1 in the FMFLMH are found and defined by theoretical analysis and numerical simulation, which are the direct caving movement type of cantilever structure (direct caving), the double‐sided rotation movement type of cantilever structure (double‐side rotation), the quadratic rotation movement type of cantilever structure (quadratic rotation), the alternative movement type of cantilever structure hinged structure (alternate hinged), the voussoir beam structure movement type (voussoir), and the short voussoir beam structure movement type (short voussoir), respectively. Besides, based on this, the support load calculation model of each movement type was established, and a formula for the support working resistance of each movement type was obtained. Finally, the correctness of the formulae for the support working resistance under six types of movement of SKS 1 were verified using measurement data from four FMFLMHs in China. These research results have important guiding significance for reasonable selection of support and ensuring safe mining of the FMFLMH. [ABSTRACT FROM AUTHOR]

Summary: This paper investigates the distributed tracking control of a group of underactuated quadrotors in the presence of actuator faults in three‐dimensional space. Using consensus protocol and sliding mode algorithm, a distributed finite‐time fault‐tolerant formation control scheme is developed. The whole closed‐loop system is composed by position loop, attitude loop, and propeller speed loop. A propeller speed fault‐tolerant controller is developed to deal with the unexpected faults of quadrotors. The finite‐time stability of the closed‐loop system is guaranteed through Lyapunov analysis. Finally, the efficiency of the proposed algorithm is illustrated by some numerical simulations. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we develop new governing equations for thermo‐gradient‐dependent theory of plasticity. They include the coupled effects of thermal elastic‐plastic theory, including balance and constitutive equations. To demonstrate the salient feature of the gradient‐dependent model of plasticity, particular attention is addressed to isotropic hardening with second sound effects to eliminate the paradox of infinite speed of thermal signals. The resulting system of partial differential equations formally describes the coupled thermomechanical behavior of the gradient‐dependent elasto‐plastic system. Then, we develop an appropriate state‐space form and, by using the semigroup theory, we prove the well‐posedness and the exponential stability of the thermo‐gradient‐dependent elasto‐plastic one‐dimensional problem. Finally, we perform numerical simulations to validate the proposed model and to show its capability. [ABSTRACT FROM AUTHOR]

Summary: Aiming to accurately simulate seismic dynamic response of rock masses using the numerical manifold method (NMM), boundary settings must be treated carefully. In this paper, 4 issues in boundary settings are investigated to improve the performance of NMM: (1) Nonreflecting boundaries including the viscous boundary and viscoelastic boundary are considered; (2) A free‐field boundary is incorporated into NMM to accurately simulate external source wave motion; (3) A seismic input boundary is considered, and the force input method is introduced; and (4) A static‐dynamic unified boundary is incorporated for the convenience of transforming displacement boundary into other types of boundaries, such as nonreflecting boundaries and seismic input boundary. Several benchmark problems are solved to validate the improved NMM. Simulation results agree well with analytical ones, indicating that the improved NMM is able to simulate seismic dynamic response of rock masses reliably and correctly. [ABSTRACT FROM AUTHOR]

Abstract: This paper summarizes a numerical and experimental investigation of free convective heat transfer in an open‐ended cavity between two horizontal parallel circular plates. The upper plate is maintained at an ambient temperature and the lower one is heated. Air is used as the heat transfer medium. The numerical model equations are solved using a control volume‐based finite differences method, and the experimental study was performed using holographic interferometry. Streamlines and isotherm patterns are presented and discussed for different aspect ratios (A) and Rayleigh numbers (Ra). Heat transfer at the surface of the lower plate is thoroughly inspected in the ranges 0.1 ≤ A ≤ 1 and 10 2 ≤ R a ≤ 5 × 10 6. Useful correlations of Nusselt numbers in terms of R a and A are given with their validity ranges. Also, an investigation of both numerical and experimental results is performed. It shows similar temperature field aspect with some differences in the radial boundary layer thickness and a small deviation in the heat transfer. [ABSTRACT FROM AUTHOR]

Computer experiments often have inputs that are proportions/fractions of components in a mixture. In these mixture computer experiments, it can be of interest to perform robust and tolerance design on the mixture proportions since the proportions are subjected to noise variations. Traditionally, manufacturing of mixture products is controlled via interval tolerances for mixture amounts. In this paper, an optimal tolerance region for proportions, which gives optimal quality cost among all possible tolerance regions for mixture proportions with the same acceptance probability, is proposed for integrated parameter and tolerance design in mixture computer experiments. Real examples are given to demonstrate the improvements that can be achieved with the optimal tolerance region. [ABSTRACT FROM AUTHOR]

Reliability demonstration test (RDT) is a critical and necessary step before the acceptance of an industrial system. Generally, a RDT focuses on designing a test plan through which one can judge whether the system reliability indices meet specific requirements. There are many established RDT plans, but few have incorporated the reliability growth aspects of the corresponding products. In this paper, we examine a comprehensive test plan that involves information concerning the reliability growth stage. An approach for RDT under the assumption of the power-law model is proposed. It combines data related to the growth stage with those pertaining to the test stage of the product to reduce the cost of the test. Through simulation studies and numerical examples, we illustrate the characteristics of the test plan and significant reduction in test costs through our approach. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Functional data and profiles are characterized by complex relationships between a response and several predictor variables. Fortunately, statistical process control methods provide a solid ground for monitoring the stability of these relationships over time. This study focuses on the monitoring of 2-dimensional geometric specifications. Although the existing approaches deploy regression models with spatial autoregressive error terms combined with control charts to monitor the parameters, they are designed based on some idealistic assumptions that can be easily violated in practice. In this paper, the independent component analysis (ICA) is used in combination with a statistical process control method as an alternative scheme for phase II monitoring of geometric profiles when non-normality of the error term is present. The performance of this method is evaluated and compared with a regression- and PCA-based approach through simulation of the average run length criterion. The results reveal that the proposed ICA-based approach is robust against non-normality in the in-control analysis, and its out-of-control performance is on par with that of the PCA-based method in case of normal and near-normal error terms. [ABSTRACT FROM AUTHOR]

SUMMARY In this paper, a propagator matrix method applied to logging-while-drilling tools is introduced and extended to deal with the anisotropic and radially inhomogeneous earth formations. This method expands the Maxwell's equations in the transverse direction, constructs the relationship between propagator matrix and reflection matrix, and obtains the solution by using the reflection matrix. We systematically derived the formulas of propagator matrix method in isotropic media, uniaxially anisotropic media, fully anisotropic media, and radially inhomogeneous media respectively. In order to obtain the propagator matrix in complex media, we used the fourth-order Runge-Kutta scheme. Numerical experiments show that, compared with traditional methods, the propagator matrix method has wide range of applications while maintaining low computational costs and high accuracy. All algorithms presented in the paper have been parallelized and implemented on a high-performance computing platform. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, a protocol and a control law are designed for a single robot so that a team of such robots can interact and cooperate to reach the displacements from an eligible reference formation. Each robot is equipped with displacement sensors of limited sensing ranges. Communication channels are assumed to be unavailable to the team, and each robot works in stealth mode. The team is scalable such that new robots can be recruited, and existing robots can be dismissed. In order for the team size to be scalable, the extended formation based on relative displacement is established as the reference formation. Thus, using the extended formation as a reference, the control law and the protocol could be flexible. As potential conflicts deflect the robot team from the desired formation, the control law is designed to expose the conflicts to the involved neighboring robots such that the protocol can resolve them. A numerical example is given to illustrate how an extended formation is designed, and a simulation example is conducted to demonstrate the performance and merits of the proposed techniques. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The human shoulder is a complicated musculoskeletal structure and is a perfect compromise between mobility and stability. The objective of this paper is to provide a thorough review of previous finite element (FE) studies in biomechanics of the human shoulder complex. Those FE studies to investigate shoulder biomechanics have been reviewed according to the physiological and clinical problems addressed: glenohumeral joint stability, rotator cuff tears, joint capsular and labral defects and shoulder arthroplasty. The major findings, limitations, potential clinical applications and modelling techniques of those FE studies are critically discussed. The main challenges faced in order to accurately represent the realistic physiological functions of the shoulder mechanism in FE simulations involve (1) subject-specific representation of the anisotropic nonhomogeneous material properties of the shoulder tissues in both healthy and pathological conditions; (2) definition of boundary and loading conditions based on individualised physiological data; (3) more comprehensive modelling describing the whole shoulder complex including appropriate three-dimensional (3D) representation of all major shoulder hard tissues and soft tissues and their delicate interactions; (4) rigorous in vivo experimental validation of FE simulation results. Fully validated shoulder FE models would greatly enhance our understanding of the aetiology of shoulder disorders, and hence facilitate the development of more efficient clinical diagnoses, non-surgical and surgical treatments, as well as shoulder orthotics and prosthetics. © 2016 The Authors. International Journal for Numerical Methods in Biomedical Engineering published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Coupling multiphysical systems by means of a co-simulation, the data between the subsystems are interchanged at a discrete macro time grid, also denoted as communication time grid. Between the communication points the coupling variables are approximated so that the numerical solvers in the subsystems can calculate the differential equations. Classical approximation techniques based on extrapolation entail a discontinuity in the equations in each macro time step which can slow down the numerical time integration. In the paper at hand a C0-continuous technique for approximating the coupling variables is reconsidered and the numerical stability and the local error of the method are compared to the classical Lagrange approximation approach. Further, the method is enhanced to a C1-continuous (continuous and differentiable) approximation technique. Both methods are investigated in combination with different numerical coupling approaches (sequential Gauss-Seidel scheme, parallel Jacobi scheme, force/displacement coupling, displacement/displacement coupling) which are commonly applied for co-simulation in technical applications. It is shown that the C1-continuous approximation technique yields a similar numerical stability and a similar local error as the Lagrange approach which results in a comparable or even better overall performance (taking into account the advantage of continuity at the numerical calculation of the subsystem differential equations). Applying the C0-continuous approach, a similar numerical stability is obtained. However, the order of the local error is significantly lower than for the C1-continuous method and the Lagrange approach. [ABSTRACT FROM AUTHOR]

This paper demonstrates the capability of our previously published undoped Double-Gate (DG) MOSFET explicit and analytical compact model to also forecast the effect of the volume inversion (VI) on the intrinsic capacitances. For that purpose, we present simulation results for these capacitances. We show now that the model presents an accurate dependence on the silicon layer thickness, consistent with two-dimensional numerical simulations, for both thin and thick silicon films. As opposed to our previous work, here we test the capacitance model for three different film thicknesses and also show that the transition from VI regime to dual gate behaviour is well simulated. We demonstrate in this paper that even if the current drive and transconductance are enhanced in VI regime, our results show that intrinsic capacitances are higher as well, which may limit the high-speed (delay time) behaviour of DG MOSFETs under VI regime. The good agreement between the numerical simulations and our model shows the high potential of our complete DG MOSFET model. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, we study a one-dimensional morphogenesis model considered by C. Stinner et al. (Math. Meth. Appl. Sci. 2012; 35: 445-465). Under homogeneous boundary conditions, we prove the existence of nonconstant positive steady states through local bifurcation theories. Then we rigorously study the stability of these nonconstant solutions when the sensitivity functions are chosen to be linear and logarithmic, respectively. Finally, we present numerical solutions to illustrate the formation of stable inhomogeneous spatial patterns. Our numerical simulations show that this model can develop very complicated and interesting structures even over one-dimensional finite domains. [ABSTRACT FROM AUTHOR]

gggggAssume that an n × n dot matrix is stored in consecutive n words of a computer with one word being n bit. This paper discusses eight operations to rotate or transpose the dot matrix in horizontal/vertical! slant direction. As is well known, such operations form a group. This paper presents a unified description of the algorithms, and it is shown that all eight algorithms can be derived by suit- ably setting the constants in the unified algorithm. Then it is shown that the algorithms can be transformed to each other by simple transformation rules for the constants, and those transformation rules are shown to form a group. The foregoing algorithms for the dot matrix are not unique, and there can be different descriptions for the algorithm producing the same result. Consequently, there can be various versions of the eight algorithms as well as versions of transformation rules. This paper shows that one of the two groups formed by the transformation rules is isomorphic to the group of algorithms, but the other is not isomorphic. [ABSTRACT FROM AUTHOR]

The transport mechanism of chloride ions in concrete during wetting and drying cycles of varying duration is evaluated in this paper. The experimental test results were used to validate a numerical simulation model in order to assess the influence of diffusion coefficient, surface chloride ion concentration and ratio of dry-wet cycle durations on the transport mechanism of chloride ions in concrete. Experimental and numerical analysis results indicate that the maximum transmission depth of chloride ions in concrete depends on the diffusion coefficient and the dry-wet cycle regime but has little relationship with the surface concentration of chloride. The chloride ion transmission in the surface zone accelerates only if the dry-wet ratio is > 1. As the dry-wet ratio increases, so the chloride ion transmission accelerates. It tends to become stable when the dry-wet ratio reaches 5:1. The dry-wet cycles accelerate the transport process of chloride ions within a certain distance from the surface; beyond this distance, chloride ions in the complete immersion specimen migrate more rapidly than those under dry-wet cycles. The peak concentration of chloride ions within the convection zone has a relationship with the diffusion coefficient, the surface chloride ion concentration and the dry-wet regime. The smaller the diffusion coefficient, the higher the surface chloride concentration; the greater the dry-wet ratio, the higher the peak of convection can be. [ABSTRACT FROM AUTHOR]

In this paper, a unified cubic flux-controlled memristor is proposed, and how to choose its parameters to obtain an appropriate memristor is investigated. The relevant frequency band of the exciting source that enables the memristor to keep its characteristics (call it mem-frequency band) is analyzed, and the matter of high mem-frequency is also clinched. Based on the trend of their i-v curves versus time, the memristors are divided into two types: P and N. The design, simulations and experiments of the circuits for the presented memristor model are given to describe its dynamical behaviors. The results from simulations and experiments are in good agreement with the theoretical analysis, which are of special guidance for designing such device to satisfy the requirements in practical engineering. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Faltwerke sind ein idealer Tragwerkstyp für den flächigen Baustoff Glas. Die hierfür notwendige linienförmige Verbindung stellt eine Herausforderung an die konstruktive Umsetzung dar. Im folgenden Beitrag werden ein experimentelles Verbindungsdetail und die zugehörigen Grenzen der Tragfähigkeit gezeigt. Ergebnissen aus Versuchen werden numerische Werte an die Seite gestellt. Der Aufsatz behandelt des weiteren Fragen zur Interaktion unter kombinierter Belastung und den Einfluss des Knickwinkels auf die Auslastung der Verbindung. Geschlossen wird mit einem Ausblick auf notwendige weiterführende Forschung. Folded Plate Structures in Glass. Folded plate structures seem an optimal structural typology for the flat and thin material glass. The required linear connection is a challenge for the joint design. This paper presents an experimental connection detail together with its loading limits. The values obtained by testing are compared to numerical results. In the following, questions related to load interaction are discussed, as well as the influence of the kink between two plates on the connection's utilisation. Limitations of digital prototyping will be touched on as well as required future research. [ABSTRACT FROM AUTHOR]

Shape optimization methods, as commonly applied in aerodynamic design applications, have recently been adapted for use in nuclear fusion divertor target design. The resulting algorithms are very efficient compared to the standard use of numerical edge plasma simulations as analysis tools only. In this paper, we highlight some numerical aspects of the underlying algorithm, focusing on a correct, nine-point discretization of the fluxes and the need for an adjoint pressure correction equation. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Digital holographic microscope allows imaging of opaque and transparent specimens without staining. A digitally recorded hologram must be reconstructed numerically at the actual depth of the object to obtain a focused image. We have developed a high-resolution digital holographic microscope for imaging amplitude and phase objects with autofocusing capability. If the actual depth of an object is not known a priori, it is estimated by comparing the sharpness of several reconstructions at different distances, which is very demanding in means of computational power when the recorded hologram is large. In this paper, we present 11 different sharpness metrics for estimating the actual focus depths of objects. The speed performance of focusing is discussed, and a scaling technique is introduced where the speed of autofocusing increases on the order of square of the scale ratio. We measured the performance of scaling on computer-generated holograms and on recorded holograms of a biological sample. We show that simulations are in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

SUMMARY This paper deals with a design problem of an adaptive output feedback control for discrete-time systems with a parallel feedforward compensator (PFC), which is designed for making the augmented controlled system 'Almost Strictly Positive Real' (ASPR). A PFC design scheme by a fictitious reference iterative tuning (FRIT) approach with only using an input/output experimental data set will be proposed for discrete-time systems in order to design an adaptive output feedback control system. Furthermore, the effectiveness of the proposed PFC design method will be confirmed through numerical simulations by designing an adaptive control system with adaptive NN (neural network) for an uncertain discrete-time system. © 2014 Wiley Periodicals, Inc. Electr Eng Jpn, 187(1): 24-32, 2014; Published online in Wiley Online Library (). DOI 10.1002/eej.22456 [ABSTRACT FROM AUTHOR]

For one-way fixed effects ANOVA, it is well known that the conventional F test of the equality of means is not robust to unequal variances, and numerous methods have been proposed for dealing with heteroscedasticity. On the basis of extensive empirical evidence of Type I error control and power performance, Welch's procedure is frequently recommended as the major alternative to the ANOVA F test under variance heterogeneity. To enhance its practical usefulness, this paper considers an important aspect of Welch's method in determining the sample size necessary to achieve a given power. Simulation studies are conducted to compare two approximate power functions of Welch's test for their accuracy in sample size calculations over a wide variety of model configurations with heteroscedastic structures. The numerical investigations show that Levy's (1978a) approach is clearly more accurate than the formula of Luh and Guo (2011) for the range of model specifications considered here. Accordingly, computer programs are provided to implement the technique recommended by Levy for power calculation and sample size determination within the context of the one-way heteroscedastic ANOVA model. [ABSTRACT FROM AUTHOR]

SUMMARY The multiport scattering (S-) parameter matrix is increasingly utilized to compose models of large bit-width interconnect systems with broadband characteristics (frequency range of zero to tens of gigahertz) to perform increasingly accurate signal-integrity and power-integrity simulations. The search for an optimal solution space often requires generation of S-parameter models of interconnect systems for various signal/ground pin mappings, a process that can be computationally costly if the structure is electromagnetically solved for each distinct pin mapping. To expedite this model-generation process, we propose a method in which an N-port structure is electromagnetically solved only once to yield an N × N S-matrix; then, a linear system is formulated and solved to yield an ( N − M) × ( N − M) post-suppressed S-matrix (where M is the number of suppressed ports). This approach results in significant computational savings through elimination of electromagnetic field-solver runs for each distinct pin mapping. Included in this paper is a discussion about the limitations of this technique and several numerical examples. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose: Low-intensity focused ultrasound has been shown to stimulate the brain noninvasively and without noticeable tissue damage. Such a noninvasive and localized neurostimulation is expected to have a major impact in neuroscience in the coming years. This emerging field will require many animal experiments to fully understand the link between ultrasound and stimulation. The primary goal of this paper is to investigate transcranial ultrasonic neurostimulation at low frequency (320 kHz) on anesthetized rats for different acoustic pressures and estimate the in situ pressure field distribution and the corresponding motor threshold, if any. The corresponding acoustic pressure distribution inside the brain, which cannot be measured in vivo, is investigated based on numerical simulations of the ultrasound propagation inside the head cavity, reproducing at best the experiments conducted in the first part, both in terms of transducer and head geometry and in terms of acoustic parameters. Methods: In this study, 37 ultrasonic neurostimulation sessions were achieved in rats (N = 8) using a 320 kHz transducer. The corresponding beam profile in the entire head was simulated in order to investigate the in situ pressure and intensity level as well as the spatial pressure distribution, thanks to a rat microcomputed tomography scan (CT)-based 3D finite differences time domain solver. Results: Ultrasound pulse evoked a motor response in more than 60% of the experimental sessions. In those sessions, the stimulation was always present, repeatable with a pressure threshold under which no motor response occurred. This average acoustic pressure threshold was found to be 0.68 ± 0.1 MPa (corresponding mechanical index, MI = 1.2 and spatial peak, pulse averaged intensity, Isppa = 7.5 W cm-2), as calibrated in free water. A slight variation was observed between deep anesthesia stage (0.77 ± 0.04 MPa) and light anesthesia stage (0.61 ± 0.03 MPa), assessed from the pedal reflex. Several kinds of motor responses were observed: movements of the tail, the hind legs, the forelimbs, the eye, and even a single whisker were induced separately. Numerical simulations of an equivalent experiment with identical acoustic parameters showed that the acoustic field was spread over the whole rat brain with the presence of several secondary pressure peaks. Due to reverberations, a 1.8-fold increase of the spatial peak, temporal peak acoustic pressure (Psptp) (±0.4 standard deviation), a 3.6-fold increase (±1.8) for the spatial peak, temporal peak acoustic intensity (Isptp), and 2.3 for the spatial peak, pulse averaged acoustic intensity (Isppa), were found compared to simulations of the beam in free water. Applying such corrections due to reverberations on the experimental results would yield a higher estimation for the average acoustic pressure threshold for motor neurostimulation at 320 KHz at 1.2 ± 0.3 MPa (MI = 2.2 ± 0.5 and Isppa = 17.5 ± 7.5 W cm-2). Conclusions: Transcranial ultrasonic stimulation is pressure- and anesthesia-dependent in the rat model. Numerical simulations have shown that the acoustic pattern can be complex inside the rat head and that special care must be taken for small animal studies relating acoustic parameters to neurostimulation effects, especially at a low frequency. [ABSTRACT FROM AUTHOR]

In this paper, we consider a three-dimensional viral model with delay. We first investigate the linear stability and the existence of a Hopf bifurcation. It is shown that Hopf bifurcations occur as the delay τ passes through a sequence of critical values. Then, using the normal form theory and center manifold reduction, we derive the explicit formulaes that determine the stability, the direction, and the period of bifurcating periodic solutions. Numerical simulations are carried out to illustrate the validity of the main results. Finally, some brief conclusions are given. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper studies a two-dimensional chemotactic model for two species in which one of them produces a chemo-repellent for the other. It is shown asymptotically and numerically how the chemical inhibits the invasion of a moving front for the second species and how stable steady states, which depend on the chemical concentration, can be reached. The results qualitatively explain experimental observations by Swain and Ray [1] showing that colonies of bacteria produce metabolite agents which prevent the invasion of fungi. [ABSTRACT FROM AUTHOR]

Numerical modelling plays an important role in helping us understand the characteristics of seismic wave propagation. The presence of spurious reflections from the boundaries of the truncated computational domain is a prominent problem in finite difference computations. The nearly perfectly matched layer has been proven to be a very effective boundary condition to absorb outgoing waves in both electromagnetic and acoustic media. In this paper, the nearly perfectly matched layer technique is applied to elastic isotropic media to further test the method's absorbing ability. The staggered-grid finite-difference method (fourth-order accuracy in space and second-order accuracy in time) is used in the numerical simulation of seismic wave propagation in 2D Cartesian coordinates. In the numerical tests, numerical comparisons between the nearly perfectly matched layer and the convolutional perfectly matched layer, which is considered the best absorbing layer boundary condition, is also provided. Three numerical experiments demonstrate that the nearly perfectly matched layer has a similar performance to the convolutional perfectly matched layer and can be a valuable alternative to other absorbing layer boundary conditions. [ABSTRACT FROM AUTHOR]

In this paper, the second in a series, the accuracy and performance of the high-order spectral volume (SV) method for moment models in device simulations is enhanced by employing the penalty and BR2 formulations for discretizing the second derivative diffusive fluxes. The potential equation is also discretized using the above formulations. The actual accuracy and the numerical orders are obtained by performing accuracy studies. An n -n-n diode was assumed for simulation purposes. The results obtained by solving steady-state hydrodynamic (HD) and energy transport (ET) models are compared with the existing local discontinuous Galerkin formulation (LDG) results. The newer formulations yield more accurate solutions than the ones which used the LDG formulation. In addition, the newer formulations converge to steady state much faster than the LDG formulation. The BR2 formulation is compact and hence can be easily parallelized. The penalty formulation is however not compact. In general, the numerical results are very promising and indicate that the newer diffusive flux formulations are more accurate, converge faster, have greater potential and hence are suited better than the LDG for higher dimensional device problems. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, the channel capacity of multiple-input multiple-output ultra-wideband (MIMO-UWB) systems with single co-channel interference (CCI) is calculated. A ray-tracing approach is used to calculate the wanted channel frequency response, and the channel frequency response is further used to calculate the corresponding channel capacity. By the ray-tracing approach, two different antenna arrays are applied to our simulation to observe whether MIMO can reduce CCI. Also the effects caused by the two antenna arrays for the desired system and CCI are quantified. Copyright © 2010 John Wiley & Sons, Ltd. Numerical results show that MIMO-PA provides a somewhat lower gain in SNR and capacity than does the MIMO-SA, but offers a feasible alternative for miniaturized UWB devices owing to its compact, collocated antenna structure, and it keeps a good immunity against the CCI. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In surgical navigation systems, system error analysis is performed because of the need for correct superposition of three-dimensional data obtained with three-dimensional position sensors and different coordinate systems for the images. Lea and colleagues proposed a registration graph for providing a systematic description with a graph of the geometrical position of the system and performing error analysis. However, the registration graph requires the explicit input of errors for each 3D data item. The authors expanded this system to automatically calculate individually occurring errors from system design information through a simulation, and to perform direct error analysis from the system design information. As a result, a user without specialized knowledge of error analysis can automatically perform error analysis by virtually designing a 3D data integration system on a computer. In this paper, the authors constructed a system simulator for modeling point-to-point registration and 3D position sensors, performing automatic error calculation with the simulation based thereon, and designing a system easily using a GUI. Furthermore, as a demonstration of the simulator, the simulator was applied to error analysis for a system including point-to-point registration and 3D position sensors, and its effectiveness and reliability were confirmed. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(8): 45–59, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20377 [ABSTRACT FROM AUTHOR]

One of the important problems of watermarking techniques is the weakness against geometrical distortions because of synchronization loss. In this paper, we propose an image compensation scheme against geometrical distortions in order to extract watermarks correctly. Our scheme collects the feature points in an image so as to recover the distortions caused by geometrical distortion attacks. Such feature points are selected by the local maximal value of partitioned regions which can be obtained by several filtering operations. Based on the computer simulated results, we have searched the optimal filtering operation and interpolation, and then studied the validity of our scheme. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 89(12): 1– 9, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20235 [ABSTRACT FROM AUTHOR]

This paper presents the fundamental surge phenomenon when a step voltage is applied to a horizontal line above the ground which has branch feeders. We study line current and voltage at joint with the method of moments that calculates electromagnetic field in frequency domain. It is widely noted that the current reflection factor changes to a third at the junction of the same three lines in conventional transmission line theory based on TEM wave, and the stepwise current reflected appears overlapping to the incident current. On the other hand, the reflected current from the joint shows the inductive characteristic or the capacitive one depending on the angle between lines, which varies gradually and not stepwise in our numerical analysis considering TM wave. The time characteristic of the voltage at joint depends on the angles also, and the peak voltage slightly exceeds the voltage by the transmission line theory. These phenomena are caused by the electromagnetic coupling between the main line and branch lines. In addition to the computer simulations, we measured the currents in the reduced-scale model lines and the results show the validity of our analysis regarding changes of the reflected current depending on the angles. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 144(2): 1–8, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.10176 [ABSTRACT FROM AUTHOR]

A bandlimited signal sampled at a sampling rate higher than the Nyquist rate can be reconstructed uniquely from its samples even when a finite number of samples is being lost. This paper gives a solution to this problem which partially originates from M arks [1]. The solution described here is available in a parallel and a sequential (iterative) form. The parallel implementation requires the solution of a single system of linear equations. Some investigation of the numerical properties of this system is done and a numerical example is given. [ABSTRACT FROM AUTHOR]

Realistic circuit design requires that unavoidable tolerances on component parameters be taken into account, particularly in situations where a circuit is to be mass-produced. Since specifications are normally imposed on circuit performance, parameter tolerances can have the undesirable effect of reducing manufacturing yield (i.e. the percentage of circuits which meet specifications) to values below unity, thereby effectively increasing circuit cost. Approaches have been developed to electrical circuit design which incorporate aspects of parameter tolerance variations at the various stages of design, thus enabling tolerance effects to be assessed and minimized. There are two principal approaches: statistical and deterministic. The first uses probabilistic techniques to predict variations in circuit performance, whereas the second uses deterministic (i.e. non- stochastic) methods. Within each group, three types of problems are important: first, the maximization of yield, secondly, the minimization of circuit-unit cost and, thirdly, the minimization of performance variability. This paper discusses some important advances in the statistical approach to tolerance design. Monte Carlo analysis is almost invariably an important component of the procedure: random fluctuations in parameter values are simulated according to some probability density function and inserted into a computer circuit simulation program which computes corresponding circuit performance variations. The procedure -- also referred to as tolerance analysis - not only allows the designer to predict expected performance fluctuations but also presents him with information regarding the relative location of acceptable and non-acceptable circuits in component parameter space. The Monte Carlo method can handle without difficult any number of component parameters and performance functions; moreover, statistical dependence among parameters is readily handled. The algorithm presented here is experimentally validated through successful design of practical circuits and is applicable to both discrete and integrated circuits. Strategies which ensure computational efficiency of the methods are discussed and a cost/benefit analysis carried out for a typical circuit. [ABSTRACT FROM AUTHOR]

Differential PCM (DPCM) has often been used for encoding of images, but its efficiency is very poor at low transmission rates. Discussion of DPCM is based on an autoregressive (AR) model which is causal In the case of raster scan sampling. However, originally, images do not satisfy causality in this sense, and a better description of the two-dimensional image Information can be obtained by an interpolative model representing the relations between neighboring pixels. This paper proposes a two-dimensional interpolative DPCM which is based on such a model. This method has the following special feature: if the output samples of a DPCM process based on a causal AR model are regarded as intermediate decoded values, then the final decoded values are yielded by a filtering process based on an Interpolative model. The results of simulation using actual images demonstrate SN ratio improvement at a low bit rate (1 bit/pel) and also the stability of encoding characteristics in the case of quantitative step-size variations. It is shown that fixing of the prediction and interpolation coefficients results only in slight deterioration. [ABSTRACT FROM AUTHOR]

The digital sinusoidal oscillator considered in this paper is one of the signal sources employed in the digital signal processing system. A construction of the oscillator is discussed where the memory capacity is reduced and the increasing rate of the noise is suppressed by interpolating the output of the oscillator of table look-up type or feedback type. A design method for the interpolation filter is presented first where no interpolation error is produced if the coefficient wordlength of the interpolation filter is infinite. Then, considering the case where the wordlength is kept finite, the hold-type sampling expander is proposed where the waveform distortion is kept low compared with the traditional zero-interpolation-type sampling rate expander. The distortion in the proposed method is analyzed where the wordlength of the interpolation filter coefficient is kept finite, and the waveform distortion is shown to be low. The increasing rate of the round-off error is examined by a computer simulation for the oscillator, which is obtained by applying the interpolation to the feedback-type oscillator. The effectiveness of the interpolation is demonstrated. Finally, a construction of the block-digital sinusoidal oscillator is shown with a smaller hardware complexity than in the traditional method, by constructing the block-structured oscillator by realizing the proposed interpolation filter as a polyphase filter. [ABSTRACT FROM AUTHOR]

The finite ring is used for efficient computation of filters. This paper discusses nonrecursive multiple filtering systems on an integer residue ring. The number theoretic transform, which is the Fourier transform on the finite ring, has been used for the design of FIR digital filter on an integer residue ring. A set of filters can be combined to a single filter on a finite ring, using the isomorphism derived from the Chinese remainder theorem. This equivalence is used to compute the outputs of the set of filters efficiently. An efficient algorithm is also presented to find a primitive 2t-th root of unity which is needed for the construction of the numbers theoretic transform. For filtering multiplicity ranging from two to five, possible choices of moduli are presented. Finally, an example and evaluations of the nonrecursive multiple filter are shown. [ABSTRACT FROM AUTHOR]

An adaptive digital. filter (orthogonal function-type ADF) composed of an orthogonal function system which can locate poles of a transfer function in arbitrary positions in the unit circle in the z plane is known as a way to improve convergence speed in the case in which input is a colored signal (such as voice). However, no sufficient theoretical investigation has been done on the reason why this ADF rapidly converges to the colored signal input. This paper derives an equivalent circuit of an orthogonal function-type ADF in the case in which poles of a transfer function are located in equal space on the unit circle in the z plane. Then the convergence speed using this equivalent circuit is considered. It is shown that the orthogonal function-type ADF is equivalent to a construction due to a periodic process of an input of the known ADF using the frequency sampling filter (frequency sampling-type ADF). In other words, even if Input is colored like voice and aperiodic process, in the orthogonal function type it is shown that orthogonality between tap coefficient inputs is preserved. Furthermore, these studied results are verified by computer simulations. [ABSTRACT FROM AUTHOR]

One of the most important measures for the construction of the active RC filter is the element sensitivity. One of the effective means to reduce the element sensitivity is the method to simulate the conventional LC filter with both ends terminated by resistors, This paper considers the realization of the low-pass filter by I,C simulation using GIC or by the node-voltage simulation. The prototype LC filter is discussed to solve the bias instability problem, which is a problem in the realization. First, an LC filter is proposed which is obtained by adding an inductor in parallel with the input resistor of the conventional doubly terminated LC filter. The method of constructing the filter is discussed. Then a method is presented to simulate the filter using GIC. Finally, the 5th-order Chebyshev low-pass filter is constructed and its characteristics are measured. The element sensitivity is analyzed using a computer, and it is verified that the proposed circuit has a low element sensitivity. [ABSTRACT FROM AUTHOR]