Effect Of White Gaussian Noise Research Articles

КОМПЛЕКСИРОВАНИЕ ДАННЫХ СИСТЕМЫ УПРАВЛЕНИЯ МОБИЛЬНЫМ ГУСЕНИЧНЫМ РОБОТОМ

Integration of information – the process of combining data to determine or predict the state of an object. The integration provides an increase in the robustness of the robot control and the accuracy of machine perception of information. The paper discusses one of the methods for integrating of the robot onboard data using the example of the mobile tracked robot data. One of the aim is showing how to obtain the Jacobi matrix of the process function and the Jacobi matrix of the observation function of the mobile robot system for subsequent data integration by the state observer, built on the basis of the Kalman filter, that can convert the robot onboard data into the elements of the state vector of the mobile robot system. Each nonzero element of the Jacobi matrix of the observation function of the system is a weight coefficient. It determines the contribution of an element of the output vector of the system corresponding to this weight coefficient to the result of information integration calculated by the Kalman filter – the state observer. The Kalman filter is a sequential recurrent algorithm for filtering information from discrete dynamical systems specified in the state space. A feature of the Kalman filter as an observer of the state of the system is the assumption that the observed system has the effect of white Gaussian noise (characterized by zero mathematical expectation) on its state.

WITHDRAWN: Statistical Properties of Low-Frequency Signals over FFT-OFDM

Abstract At the present, many medical and military institutions need to transmit data reliably and accurately; thus, any impact on the signal leads to a change of information and affects the patient’s life at the health level or confidential information in the case of military institutions. In this paper, we tested low-frequency signals represented by electroencephalography (EEG) and speech signals; these signals transmitted through the OFDM system. The transmitted signal affected by noise and distortion. We tested these effects of white Gaussian noise (WGN) on the statistical properties of the low-frequency signals. The similarity methods (Tanimoto similarity coefficient, Pearson correlation coefficient, and Mel-frequency cepstral coefficients) are applied to measure the differences between the original and the received version of EEG and speech signal. Simulation results showed the Tanimoto coefficients more resistant against noise for EEG, while MFCC has a high-efficiency noise resistance for the speech signal.

Compressive Sensing over OFDM Systems

Communications development is the fastest-growing Nowadays, so the need and the constant demand for
 faster and more reliable communication methods have increased. Here, the compressive sensing appeared to meet
 this need. Compressive sensing is a new method of sampling that is not rendered to the Shannon-Nyquist law. In this
 thesis, we studied the effects of orthogonal (Fourier and wavelet) modulation with compressive sensing modeling on
 the characteristics of the signal that are used for medical and security applications. The compressed image
 performance has been tested in three ways and transmitted via the FFT-OFDM system and the DWT-OFDM system,
 under various baseband modulation schemes with the effect of white Gaussian noise. Then we compared the
 transmission performance via FFT-OFDM versus DWT-OFDM. From the simulation is observed that the wave-based
 OFDM system is better than the Fourier-based OFDM system Furthermore, the wavelets better than Fourier in the
 utilization of Bandwidth, Unlike FFT that allocates part of Bandwidth of the cyclic prefix (CP), and thus part of it is
 wasted.

Effects of white Gaussian noise on dynamic balance in healthy young adults

It has been known that short-time auditory stimulation can contribute to the improvement of the balancing ability of the human body. The present study aims to explore the effects of white Gaussian noise (WGN) of different intensities and frequencies on dynamic balance performance in healthy young adults. A total of 20 healthy young participants were asked to stand at a dynamic balance force platform, which swung along the x-axis with an amplitude of ± 4° and frequency of 1 Hz. Their center of pressure (COP) trajectories were recorded when they were stimulated by WGN of different intensities (block 1) and different frequencies (block 2). A traditional method and detrended fluctuation analysis (DFA) were used for data preprocessing. The authors found that only with 75–85 dB WGN, the COP parameters improved. WGN frequency did not affect the dynamic balance performance of all the participants. The DFA results indicated stimulation with 75 dB WGN enhanced the short-term index and reduced the crossover point. Stimulation with 500 Hz and 2500 Hz WGN significantly enhanced the short-term index. These results suggest that 75 dB WGN and 500 Hz and 2500 Hz WGN improved the participants’ dynamic balance performance. The results of this study indicate that a certain intensity of WGN is indispensable to achieve a remarkable improvement in dynamic balance. The DFA results suggest that WGN only affected the short-term persistence, indicating the potential of WGN being considered as an adjuvant therapy in low-speed rehabilitation training.

Stochastic resonance in a metal-oxide memristive device

Abstract The stochastic resonance phenomenon has been studied experimentally and theoretically for a state-of-art metal-oxide memristive device based on yttria-stabilized zirconium dioxide and tantalum pentoxide, which exhibits bipolar filamentary resistive switching of anionic type. The effect of white Gaussian noise superimposed on the sub-threshold sinusoidal driving signal is analyzed through the time series statistics of the resistive switching parameters, the spectral response to a periodic perturbation and the signal-to-noise ratio at the output of the nonlinear system. The stabilized resistive switching and the increased memristance response are revealed in the observed regularities at an optimal noise intensity corresponding to the stochastic resonance phenomenon and interpreted using a stochastic memristor model taking into account an external noise source added to the control voltage. The obtained results clearly show that noise and fluctuations can play a constructive role in nonlinear memristive systems far from equilibrium.

Model of Satellite Communication Channel Functioning under Conditions of Disturbances of Service Part of Frames by Unsteady Interference

The paper describes the main ways of organizing modern satellite communication systems and the methods of synchronization and transmission of service information used in them, the frame synchronization mechanism from the view point of noise immunity. Based on the analysis, a block diagram of a simulation model is proposed for studying the influence of unintentional interference on the channels of modern satellite communication systems. The proposed model of the impact of non-stationary interference on a satellite communication channel takes into account the effect of interference on symbolic, frame synchronization, mechanisms for extracting frame boundaries, as well as the effect of modern error correction codes. The model allows evaluating the impact of non-stationary interference on both the information and the service side of the frame of modern systems of broadband satellite communications. As an indicator of the noise immunity of a satellite communication channel, there was used probability of frame loss, i.e. frame skipping due to a violation in the frame synchronization system, incorrect allocation of frame boundaries, or the presence of errors in the frame that were not repaired by corrective codes. Using this model, we studied the effect of non-stationary interference of various durations on the information and service parts of the frame, compared the results of the impact of non-stationary interferences of various durations with the effect of white Gaussian noise. It is shown that non-stationary interference, which are short noise pulses that do not affect the information part of the frame due to reparation by correction codes, can significantly reduce the reception quality due to disruption of frame synchronization and distortion of service information about the signal-code structure and frame length.

Delayed-decision making in noisy bistable switches

Bistable switches are frequently encountered in biological systems. Typically, a bistable switch models a binary decision where each decision corresponds to one of the two stable equilibria. Recently, we showed that the global decision-making process in bistable switches strongly depends on a particular equilibrium point of these systems, their saddle point. In particular, we showed that a saddle point with a time-scale separation between its attractive and repulsive directions can delay the decision-making process. In this paper, we study the effects of white Gaussian noise on this mechanism of delayed decision-making induced by the saddle point. Results show that the mean decision-time strongly depends on the balance between the initial distance to the separatrix and the noise strength.

Multiple-dwell and sequential code acquisition with diversity for FFH/MFSK spread-spectrum systems under band multitone jamming

Pseudonoise code acquisition is investigated for constant hopping rate fast frequency-hopped (FFH)/M-ary frequency-shift keying systems under the effects of white Gaussian noise and band multitone jamming. In particular, serial search acquisition systems based on the traditional multiple-dwell test (up to three dwells) and three novel sequential tests are analyzed and compared. Analytical results show the following in a heavily jammed environment: (1) the inherent time diversity in an FFH system can significantly improve the acquisition performance of the multiple-dwell test and (2) the novel sequential tests can significantly outperform the multiple-dwell test. Our analytical results are verified by computer simulations.

Code acquisition with diversity combining for FFH/MFSK spread spectrum systems

Pseudonoise code acquisition based on hard-decision and clipped diversity combining is investigated for fast frequency-hopped MFSK systems under the effects of white gaussian noise, band multitone jamming and multipath fading. Multipath fading may affect the signal or jamming channel or both. An analytical method is developed to evaluate the mean acquisition time and the operating characteristics of the acquisition system for various jamming and channel conditions. Numerical results show that the time diversity offered by a fast hopper can provide a significant performance improvement and may be indispensable in some cases to obtain a satisfactory performance; the clipped diversity combining outperforms the hard-decision diversity combining, and under some jamming and channel conditions the performance difference of these two methods can be significant; and multipath fading on the signal path degrades the acquisition performance. 1–4 dB degradation is observed, whereas fading on the jamming path reduces the effectiveness of a jamming signal. Computer simulations are also conducted to substantiate the analytical results.

Theoretical discrimination of thin-wire aircraft targets using single-mode extraction pulses

Aspect-independent single-mode extraction pulses (S-pulses) are used in conjunction with scattered field computations to discriminate between thin-wire aircraft targets. The effect of white Gaussian noise in the target returns is considered. It is shown that noise in the target returns tends to limit the reliable application of the method to an intermediate interval (window) of time which occurs after reception of the forced response. >

A Kalman filter approach for accurate 3-D motion estimation from a sequence of stereo images

This paper presents a Kalman filter approach for accurately estimating the 3-D position and orientation of a moving object from a sequence of stereo images. Emphasis is given to finding a solution for the following problem incurred by the use of a long sequence of images: the images taken from a longer distance suffer from a larger noise-to-signal ratio, which results in larger errors in 3-D reconstruction and, thereby, causes a serious degradation in motion estimation. To this end, we have derived a new set of discrete Kalman filter equations for motion estimation: (1) The measurement equation is obtained by analyzing the effect of white Gaussian noise in 2-D images on 3-D positional errors (instead of directly assigning Gaussian noise to 3-D feature points) and by incorporating an optimal 3-D reconstruction under the constraints of consistency satisfaction among 3-D feature points. (2) The state propagation equation, or the system dynamic equation, is formulated by describing the rotation between two consecutive 3-D object poses, based on quaternions and representing the error between the true rotation and the nominal rotation (obtained by 3-D reconstruction) in terms of the measurement noise in 2-D images. Furthermore, we can estimate object position from the estimation of object orientation in such a way that an object position can be directly computed once the estimation of an object orientation is obtained. Simulation results indicate that the Kalman filter equations derived in this paper represent an accurate model for 3-D motion estimation in spite of the first-order approximation used in the derivation. The accuracy of this model is demonstrated by the significant error reduction in the presence of large triangulation errors in a long sequence of images and by a shorter transition period for convergence to the true values.