Simplified Minimum Fourth-Order Moment Haze Channel Equalization Algorithm

2019 ◽  
Author(s):  
Tao Yuan ◽  
GuoYi Wang
Keyword(s):  
Fourth Order ◽  
Channel Equalization ◽  
Order Moment ◽  
Equalization Algorithm

Network Intrusion Feature Map Node Equalization Algorithm Based on Modified Variable Step-Size Constant Modulus

2019 ◽  
Vol 33 (14) ◽  
pp. 1955015 ◽  
Author(s):  
Jiazhong Lu ◽  
Xiaolei Liu ◽  
Teng Hu ◽  
Jianwei Zhang ◽  
Xiaosong Zhang
Keyword(s):  
Channel Model ◽  
Channel Equalization ◽  
Variable Step Size ◽  
Transmission Channel ◽  
Constant Modulus ◽  
Step Size ◽  
Feature Map ◽  
Network Intrusion ◽  
Equalization Algorithm ◽  
Variable Step

When the network is subject to intrusion and attack, the node output channel equalization will be affected, resulting in bit error and distortion in the output of network transmission symbols. In order to improve the anti-attack ability and equalization of network node, a network intrusion feature map node equalization algorithm based on modified variable step-size constant modulus blind equalization algorithm (MISO-VSS-MCMA) is proposed. In this algorithm, the node transmission channel model after network intrusion is constructed, and sequential processing is performed to intruded nodes with the variable structure feedback link control method. With diversity spread spectrum technology, the channel loss after network intrusion is compensated and the network intrusion map feature is extracted. According to the extracted feature amount, channel equalization processing is performed for the cost function with the MISO-VSS-MCMA method to reduce the damage of network intrusion to the channel. Simulation results show that in node transmission channel equalization after network intrusion, this algorithm can reduce the error bit rate of signal transmission in network, and provide a good ability of correcting phase deflection in the output constellation, thus avoiding the error bit distortion and channel damage caused by network intrusion to the signal with a good equalization effect. This algorithm provides stronger convergence and map concentration, which demonstrates that its anti-interference and signal recovery capabilities are better, so it improves the anti-attack ability of the network.

scholarly journals An introductory guide to fluid models with anisotropic temperatures. Part 2. Kinetic theory, Padé approximants and Landau fluid closures

2019 ◽  
Vol 85 (6) ◽  
Author(s):  
P. Hunana ◽  
A. Tenerani ◽  
G. P. Zank ◽  
M. L. Goldstein ◽  
G. M. Webb ◽  
...  
Keyword(s):  
Kinetic Theory ◽  
Fourth Order ◽  
Low Frequency ◽  
Padé Approximants ◽  
Landau Damping ◽  
Order Moment ◽  
Fluid Models ◽  
Frequency Limit ◽  
Long Wavelength ◽  
Pade Approximants

In Part 2 of our guide to collisionless fluid models, we concentrate on Landau fluid closures. These closures were pioneered by Hammett and Perkins and allow for the rigorous incorporation of collisionless Landau damping into a fluid framework. It is Landau damping that sharply separates traditional fluid models and collisionless kinetic theory, and is the main reason why the usual fluid models do not converge to the kinetic description, even in the long-wavelength low-frequency limit. We start with a brief introduction to kinetic theory, where we discuss in detail the plasma dispersion function $Z(\unicode[STIX]{x1D701})$ , and the associated plasma response function $R(\unicode[STIX]{x1D701})=1+\unicode[STIX]{x1D701}Z(\unicode[STIX]{x1D701})=-Z^{\prime }(\unicode[STIX]{x1D701})/2$ . We then consider a one-dimensional (1-D) (electrostatic) geometry and make a significant effort to map all possible Landau fluid closures that can be constructed at the fourth-order moment level. These closures for parallel moments have general validity from the largest astrophysical scales down to the Debye length, and we verify their validity by considering examples of the (proton and electron) Landau damping of the ion-acoustic mode, and the electron Landau damping of the Langmuir mode. We proceed by considering 1-D closures at higher-order moments than the fourth order, and as was concluded in Part 1, this is not possible without Landau fluid closures. We show that it is possible to reproduce linear Landau damping in the fluid framework to any desired precision, thus showing the convergence of the fluid and collisionless kinetic descriptions. We then consider a 3-D (electromagnetic) geometry in the gyrotropic (long-wavelength low-frequency) limit and map all closures that are available at the fourth-order moment level. In appendix A, we provide comprehensive tables with Padé approximants of $R(\unicode[STIX]{x1D701})$ up to the eighth-pole order, with many given in an analytic form.

Evaluation on Safety of In-Service Structures Concerning Earthquake Resistance Based on Fourth-Order Moment of Limit State Function

2014 ◽  
Vol 1065-1069 ◽  
pp. 2319-2322
Author(s):  
Yu Ying Wang ◽  
Ya Zhou Sun ◽  
Le Yang Feng
Keyword(s):  
Bearing Capacity ◽  
Fourth Order ◽  
Structural Damage ◽  
Limit State ◽  
Decisive Role ◽  
Order Moment ◽  
State Function ◽  
Limit State Function ◽  
Engineering Structures ◽  
Internal Factors

During the process of being used, engineering structures will undergo material aging and structural damage with time passing by under the combined influence of internal factors including load, environment and structural material[1], and accumulation of such damages will cause decrease of bearing capacity, durability and reliability. Among various factors influencing the reliability of in-service structures, ultimate bearing capacity plays the decisive role in safety. In this paper, the fourth-order moment of limit state function is inferred through calculation of failure probability of in-service structures, and thus safety and durability of in-service structures can be ensured.

Reliability Analysis of Mechanical Systems Based on the First Four Moments of Input Parameters

2020 ◽  
Author(s):  
Singiresu S. Rao ◽  
Yang Zhou
Keyword(s):  
Reliability Analysis ◽  
Fourth Order ◽  
Probability Distributions ◽  
Limit State ◽  
Moment Function ◽  
Design Parameters ◽  
Order Moment ◽  
State Function ◽  
Exact Probability ◽  
First Four Moments

Abstract The performance of a mechanical or structural system can be improved through a proper selection of its design parameters such as the geometric dimensions, external actions (loads) and material characteristics. The computation of the reliability of a system, in general, requires a knowledge of the probability distributions of the parameters of the system. It is known that for most practical systems, the exact probability distributions of the parameters are not known. However, the first few moments of the parameters of the system may be readily available in many cases from experimental data. The determination of the reliability and the sensitivity of reliability to variations or fluctuations in the parameters of the system starts with the establishment of a suitable limit state equation. This work presents a reliability analysis approach for mechanical and structural systems using the fourth order moment function for approximating the first four moments of the limit state function. By combining the fourth-order moment function with the probabilistic perturbation method, numerical methods are developed for finding the reliability and sensitivity of reliability of the system. An automobile brake and a power screw are considered for demonstrating the methodology and effectiveness of the proposed computational approach. The results of the automobile brake are compared with those given by the Monte Carlo method.

scholarly journals Modified Blind Equalization Algorithm Based on Cyclostationarity for Contaminated Reference Signal in Airborne PBR

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 788
Author(s):  
Shuai Guo ◽  
Jun Wang ◽  
Hui Ma ◽  
Jipeng Wang
Keyword(s):  
Blind Equalization ◽  
Reference Signal ◽  
Back Propagation ◽  
Doppler Frequency ◽  
Phase Constraint ◽  
Order Moment ◽  
Equalization Algorithm ◽  
Source Signal ◽  
Multipath Signal ◽  
Multipath Signals

In airborne passive bistatic radar (PBR), the reference channel toward the opportunity illuminator is applied to receive the direct-path signal as the reference signal. In the actual scenario, the reference signal is contaminated by the multipath signals easily. Unlike the multipath signal in traditional ground PBR system, the multipath signal in the airborne PBR owns not only the time delay but also the Doppler frequency. The contaminated reference signal can cause the spatial-temporal clutter spectrum to expand and the false targets to appear. The performance of target detection is impacted severely. However, the existing blind equalization algorithm is unavailable for the contaminated reference signal in airborne PBR. In this paper, the modified blind equalization algorithm is proposed to suppress the needless multipath signal and restore the pure reference signal. Aiming at the Doppler frequency of multipath signal, the high-order moment information and the cyclostationarity of source signal are exploited to construct the new cost function for the phase constraint, and the complex value back propagation (BP) neural network is exploited to solve the constraint optimization problem for the better convergence. In final, the simulation experiments are conducted to prove the feasibility and superiority of proposed algorithm.

A Modified DFE-MMSE Equalization Algorithm

2014 ◽  
Vol 981 ◽  
pp. 444-449
Author(s):  
Yu Xia ◽  
Fang Ye ◽  
Yi Bing Li ◽  
Ling Wang
Keyword(s):  
Bit Error Rate ◽  
Channel Equalization ◽  
Wireless Channel ◽  
Decision Feedback ◽  
Error Diffusion ◽  
Signal Distortion ◽  
Iterative System ◽  
Equalization Algorithm ◽  
Simulation Results ◽  
Time Offset

In wireless communication, inter symbol interference (ISI) and signal distortion are often caused by the frequency deviation and time offset of wireless channel. To eliminate or reduce ISI, people proposed the channel equalization technology. However, traditional decision feedback equalization algorithm based on MMSE criterion equalizer (DFE-MMSE) often introduces the error diffusion which degrades the performance of the equalizer in iterative system. In this paper, we propose an improved DFE-MMSE algorithm to reduce the error diffusion and improve the performance of iterative equalization, with a correction factor. Simulation results show that our algorithm achieves better bit error rate, which makes it competent in more practical cases.

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