Traveling waves

New treatments for Alzheimer's disease require early detection of cognitive decline. Most studies seeking to identify markers of early cognitive decline have focused on a limited number of measures. We sought to establish the profile of brain function measures which best define early neuropsychological decline. We compared subjects with subjective memory complaints to normative controls on a wide range of EEG derived measures, including a new measure of event-related spatio-temporal waves and biophysical modeling, which derives anatomical and physiological parameters based on subject's EEG measurements. Measures that distinguished the groups were then related to cognitive performance on a variety of learning and executive function tasks. The EEG measures include standard power measures, peak alpha frequency, EEG desynchronization to eyes-opening, and global phase synchrony. The most prominent differences in subjective memory complaint subjects were elevated alpha power and an increased number of spatio-temporal wave events. Higher alpha power and changes in wave activity related most strongly to a decline in verbal memory performance in subjects with subjective memory complaints, and also declines in maze performance and working memory reaction time. Interestingly, higher alpha power and wave activity were correlated with improved performance in reverse digit span in the subjective memory complaint group. The modeling results suggest that differences in the subjective memory complaint subjects were due to a decrease in cortical and thalamic inhibitory gains and slowed dendritic time-constants. The complementary profile that emerges from the variety of measures and analyses points to a nonlinear progression in electrophysiological changes from early neuropsychological decline to late-stage dementia, and electrophysiological changes in subjective memory complaint that vary in their relationships to a range of memory-related tasks.

Keywords: Subjective memory complaint; cognition; EEG; Traveling waves; Biophysical model; Neural synchrony; International database

menjadi orang tua harus memerlukan bekal ilmu agar nantinya ketika mempunyai anak sudah siap secara fisik dan mental. Bekal yang dibutuhkan tidak hanya materi tetapi juga pendidikan dalam mengasuh anak dan mengelola konflik dalam berkeluarga.

Article history: This article presents a fast and accurate fault location approach for power transmission lines based on the theory of traveling waves. In fact, when faults occur, they give rise to transient voltages and currents that propagate at a speed close to that of light along the transmission line as traveling waves. Moreover, according to the superposition theorem, each of these transients is a combination of a steady-state quantity and an incremental quantity. These transient signals measured at both ends of the line are first transformed to the Clarke (0-α-β components) components in order to categorize the type of faults, and then multi-scale morphological gradient filters are used to extract equivalent quantities to the incremental quantities to form what are called characteristic signals. These latter will be used to identify the fault location according to the proposed algorithm.

In this article, we investigate the traveling wave solutions to the Klein-Gordon equation in (2+1)-dimension with special types of nonlinearity. The types include quadratic, cubic and polynomial nonlinearity. The Klein-Gordon equation assumes a significant role in numerous types of scientific investigation such as in quantum field theory, nonlinear optics, nuclear physics, magnetic field etc. To investigate the aimed traveling wave solutions, we execute the (G'?G)-expansion method. The attained solutions are in the form of hyperbolic, trigonometric and rational functions. The results acknowledged that the applied method is very efficient and suitable for discovering differential equations with various types of nonlinearity considered in optics and quantum field theory. The solutions of the Klein-Gordon equation with quadratic, cubic, and polynomials nonlinearity play a significant role in many scientific measures notably optics and quantum field theory.

A high-impedance fault is generated when an overhead power line physically breaks and falls to the ground. Such faults are difficult to detect and locate in electric power systems because of the small currents and voltage drops involved, which
cannot be detected by conventional protection. Furthermore, arcing accompanies high-impedance faults, resulting in fire hazard, damage to electrical equipment, and risk to human life. This article presents an analytical description of the interaction between the electric arc associated with high-impedance faults and a transmission line. A joint analytical solution to the wave equation for a transmission line and a non-linear equation of the arc model is found for the case of an arbitrary reflection coefficient at the substation end, and a methodology for high-impedance fault detection and localization is proposed. The developed model is validated by means of a comparison
with measurements. The comparison demonstrates the accuracy and effectiveness of the proposed model.

Combustion is a fast oxidation process and exhibits diverse behaviors according to experimental conditions. When there is no natural convection of air, such as in experiments aboard a space shuttle or in a vertically confined system, an unexpected finger-like smoldering combustion develops. In this paper, a reaction-diffusion-advection system that describes smoldering combustion is studied from the viewpoint of computer-aided analysis. In particular, we focus on the traveling wave solutions of the system, which represent the characteristic propagation of combustion. It is revealed that the existence or nonexistence of stable traveling wave solutions determines whether or not a combustion front propagates in a self-sustained way in one space dimension. In two space dimensions, we numerically suggest the existence of a traveling spot solution in which the flow rate is too low to support planar traveling wave solutions. Moreover, we discuss reflection phenomena of a combustion wave when it reaches the boundary of the system.

A mechanical wave is generated as a result of an oscillating
body interacting with the well-defined medium and it propagates through that medium transferring energy
from one location to another. The ability to generate and control the motion of the mechanical waves through
the finite medium opens up the opportunities for creating novel actuation mechanisms. The focus of this study is on
understanding the traveling wave generation and propagation by establishing the relationships that illustrate the role of structural and electromechanical parameters. A brass be
a m with free-free boundary conditions was selected to be the medium through which the wave propagation occurs. Two piezoelectric elements were bonded on the opposite ends of the beam and were used to generate the controlled oscillations.
Excitation of the piezoelectrics results in coupled system dynamics that can be translated into generation of the
waves with desired characteristics. Theoretical analysis based on the distributed parameter model and experiments were conducted to provide the comprehensive understanding of the wave generation and propagation behavior.

We consider a paradigmatic nonvariational scalar Swift-Hohenberg equation that describes short wavenumber or large wavelength pattern forming systems. This work unveils evidence of the transition from stable stationary to moving localized structures in one spatial dimension as a result of a parity breaking instability. This behavior is attributed to the nonvariational character of the model. We show that the nature of this transition is supercritical. We characterize analytically and numerically this bifurcation scenario from which emerges asymmetric moving localized structures. A generalization for two-dimensional settings is discussed.

We consider a lattice equation modelling one-dimensional metamaterials formed by a discrete array of nonlinear resonators. We focus on periodic travelling waves due to the presence of a periodic force. The existence and uniqueness results of periodic travelling waves of the system are presented. Our analytical results are found to be in good agreement with direct numerical computations.

In this paper, the modified simple equation method (MSEM) is applied to construct exact solutions of the generalized (2+1)-dimensional nonlinear evolution equations (NLEEs) involving parameters via the (2+1)-dimensional Calogero-Bogoyavlenskii-Schiff (CBS) equation, the (2+1)-dimensional breaking soliton equation and the (2+1)-dimensional Bogoyavlenskii’s breaking soliton equation. The solitary wave solutions are derived from the exact solutions by assigning special values of the parameters.

This paper investigates how correlating cross-domain big data from the lightning surge and the traveling wave measurements in time and space can be used to improve fault location accuracy. The integration and correlation of big data in time and space using Global Positioning System and Geographic Information System respectively improves knowledge about faults on transmission lines caused by lightning. The benefits of proposed method are: a) the decision process can be accelerated through automation, and b) better accuracy of fault location result can be provided due to the data correlation. The benefit is a more efficient outage management procedure.