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Research of the multi-way connectivity probability for platoon-based vehicle-to-infrastructure communication network

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The Journal of China Universities of Posts and Telecommunications 2016年第1期23卷 1-7页

作者： Shao Caixing zhang jianhua College of Computer Science and Technology Southwest University for Nationalities

Vehicles travelling as platoons can reduce the huge traffic jams on the highway. Platoon members can share vehicle information such as speed and acceleration via vehicular ad hoc networks （VANETs） communication to maintain a constant inter-vehicle and inter-platoon distances. However, connectivity is a fundamental measurement to indicate the linking quality of VANETs. This paper analyzes the access and connectivity probability between the vehicles and the road side units （RSUs） of the multi-way platoon-based VANETs with roadside infrastructure. We denote the connectivity probability as the probability that the vehicles on the highway can access to at least one RSU besides the road within a designated number of hops. Moreover, besides considering the connection on the same road, we study the connection between the vehicles and the RSU via vehicles on the nearby neighbor roads. The analytical results have been validated by simulations and results show that the connectivity probability can be improved when there are platoons in a network. Meanwhile, the connectivity probability is higher in the multi-way vehicle-to-infrastructure （V2I） communication network than that in a one-way V2I communication network. The results in this paper can help to reduce the jams on the highway and achieve intelligent driving. Then the safety and comfort of the drivers and passengers on the highway can be improved. Moreover, these results can provide forceful theoretical support to the future intelligent transportation system （ITS） design.

关键词： VANETs V2I communication platoon connectivity probability multi-way

GENERALIZED CONJUGATE A-ORTHOGONAL RESIDUAL SQUARED METHOD FOR COMPLEX NON-HERMITIAN LINEAR SYSTEMS

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Journal of Computational Mathematics 2014年第3期32卷 248-265页

作者： jianhua zhang Hua Dai Department of Mathematics Nanjing University of Aeronautics and Astronautics Nanjing 210016 China Department of Mathematics Anhui Science and Technology University Fengyang 233100 China Department of Mathematics Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

Recently numerous numerical experiments on realistic calculation have shown that the conjugate A-orthogonal residual squared （CORS） method is often competitive with other popular methods. However, the CORS method, like the CGS method, shows irreg- ular convergence, especially appears large intermediate residual norm, which may lead to worse approximate solutions and slower convergence rate. In this paper, we present a new product-type method for solving complex non-Hermitian linear systems based on the bicon- jugate A-orthogonal residual （BiCOR） method, where one of the polynomials is a BiCOR polynomial, and the other is a BiCOR polynomial with the same degree corresponding to different initial residual. Numerical examples are given to illustrate the effectiveness of the proposed method.

关键词： Krylov subspace BiCOR method CORS method Complex non-Hermitianlinear systems.

NUMERICAL CALCULATION OF SOLID-LIQUID T WO PHASE FLOW BETWEEN STAY VANES IN HYDRAULIC TURBINE

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Journal of Hydrodynamics 2000年第3期12卷 110-116页

作者： zhang, jianhua Wang, Guoqiang Shanghai Jiaotong Univ Shanghai China

In this paper, an energy equation of silt-laden water flow is educed based on the energy equation of continuum fluid flow. The dissipation functions of liquid phase and solid phase are presented respectively. Then the extremity law of energy dissipation rate is introduced for the research of the silt-laden water flow and a new mathematical model is developed. The corresponding procedure based on the finite difference method (FDM) is developed to calculate the two phase flow in hydraulic turbine. The method is applied to analyze the silt-laden water flow between stay vanes, and the numerical results are in good agreement with the experimental ones.

关键词： Energy dissipation Finite difference method Flow of water Hydraulic turbines Mathematical models Numerical analysis

Compressed sensing based multi-rate sub-Nyquist sampling system

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The Journal of China Universities of Posts and Telecommunications 2015年第2期22卷 89-95页

作者： Xiong Yanwei zhang jianhua zhang Ping Key Laboratory of Universal Wireless Communication Beijing University of Post and Telecommunications

Signal sampling is a vital component in modem information technology. As the signal bandwidth becomes wider, the sampling rate of analog-to-digital conversion （ADC） based on Shannon-Nyquist theorem is more and more high and may be beyond its capacity. However the analog to information converter （AIC） based on compressed sensing （CS） is designed to sample the analog signals at a sub-Nyquist sampling rate. A new multi-rate sub-Nyquist sampling （MSS） system was proposed in this article, it has one mixer, one integrator and several parallel ADCs with different sampling rates. Simulation shows the signals can be reconstructed in high probability even though the sampling rate is much lower than the Nyquist sampling rate.

关键词： CS sub-Nyquist rate AIC MSS

Investigation on the spatial-polarizational correlation based on 3GPP spatial channel model

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Science China(Information Sciences) 2014年第2期57卷 80-91页

作者： NIE Xin zhang jianhua zhang Ping Beijing Institute of Spacecraft System Engineering Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and Telecommunications

The correlation among signals arriving at diferent elements of the antenna array has a significant impact on the performance of multiple-input multiple-output(MIMO)*** investigate the inter-element correlation when slant polarized antennas are used,a general approach for calculating the correlation coefcient is proposed based on a model that incorporates the antenna configuration,namely the antenna spacing and the slant angle,as well as the channel parameters,such as the power azimuth spectrum(PAS)and the crosspolarization discrimination(XPD).By applying this method to the 3rd generation partnership project(3GPP)spatial channel model(SCM),the expression of the inter-element correlation when the PAS follows the Laplacian distribution is *** approximate expressions are also given for two special cases,i.e.,the case where the angular spread(AS)of the PAS is small,and the case where the AS is so large that the PAS can be approximated by the uniform *** these expressions,the impact of the antenna configuration and the channel parameters on the correlation is *** that,the trend of inter-element correlation with the slant angle is ***,the equivalent relation between the slant angle and the antenna spacing is *** results can provide guidelines for the antenna configuration under diferent propagation conditions.

关键词： inter-element correlation slant polarized antennas power azimuth spectrum cross-polarization discrimination

Kinematics Analysis of Mechanisms Based on Virtual Assembly

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Chinese Journal of Mechanical Engineering 2010年第6期23卷 748-757页

作者： zhang Zhixian LIU jianhua NING Ruxin School of Mechanical Engineering Beijing Institute of Technology Beijing 100081 China

Currently, virtual assembly technology has attracted increasing attention due to considerations of solving assembly problems in virtual environment before actual assembly in manufactory. Previous studies on kinematic analysis of mechanism only aim at analyzing motion law of single mechanism, but can not simulate the multi-mechanisms motion process at the same time, let alone simulating the automatic assembly process of products in a whole assembly workshop. In order to simulate the assembly process of products in an assembly workshop and provide effective data for analyzing mechanical performance after finishing assembly simulation in virtual environment, this study investigates the kinematics analysis of mechanisms based on virtual assembly. Firstly, in view of the same function of the kinematic pairs and the assembly constraints on restricting the motion of components （subassembly or part）, the method of identifying kinematic pairs automatically based on assembly constraints is presented. The information of kinematic pairs can be obtained through calculating the constraint degree of the assembly constraints. Secondly, the incidence matrix eliminating element method is proposed in order to search the information and establish the models of mechanisms automatically after finishing assembly simulation in virtual environment. Both methods have important significance for reducing the workload of pretreatment and promoting the level of automation of kinematics analysis. Finally, the method of kinematics analysis of mechanisms is presented. Based on Descartes coordinates, three types of kinematics equations are formed. The parameters, like displacement, velocity, and acceleration, can be obtained by solving these equations. All these data are important to analyze mechanical performance. All the methods are implemented and validated in the prototype system virtual assembly process planning（VAPP）. The mechanism models are established and simulated in the VAPP system, and t

关键词： virtual assembly assembly constraint constraint degree eliminating element method kinematics equations,kinematics analysis

Research on vacuum plume and its effects

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Chinese Journal of Aeronautics 2013年第1期26卷 27-36页

作者： He Bijiao zhang jianhua Cai Guobiao School of Astronautics Beihang University

In vacuum environment, the exhaust flow of attitude control thrusters would expand freely and produce the plume, which possibly causes undesirable contamination, aerodynamic force and heating effects to the spacecraft. Plume work station （PWS） is developed by Beihang University （BUAA） for numerically simulating the vacuum plume and its effects. An approach which combines the direct simulation Monte Carlo （DSMC） method and difference solution of Navier-Stokes （N-S） equations is applied. The internal flows in nozzles are simulated by solving the NS equations. The flow parameters at nozzle exit are used as the inlet boundary condition for the DSMC calculation. Experimental studies are carried out in a supersonic low density wind tunnel which could simulate the 60-80 km altitude environment to investigate the plume and its effects. To demonstrate the capability of PWS, numerical simulations are performed for the vacuum plume of several typical attitude control thrusters. The research results are of great help for the engineering design.

关键词： Attitude control Effects Experiments Monte Carlo methods Vacuum plume

Adversarial Training-Aided Time-Varying Channel Prediction for TDD/FDD Systems

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China Communications 2023年第6期20卷 100-115页

作者： Zhen zhang Yuxiang zhang jianhua zhang Feifei Gao State Key Lab of Networking and Switching Technology Beijing University of Posts and TelecommunicationsBeijing 100876China Institute for Artificial Intelligence Tsinghua UniversityBeijing 100084China

In this paper, a time-varying channel prediction method based on conditional generative adversarial network(CPcGAN) is proposed for time division duplexing/frequency division duplexing(TDD/FDD) systems. CPc GAN utilizes a discriminator to calculate the divergence between the predicted downlink channel state information(CSI) and the real sample distributions under a conditional constraint that is previous uplink CSI. The generator of CPcGAN learns the function relationship between the conditional constraint and the predicted downlink CSI and reduces the divergence between predicted CSI and real *** capability of CPcGAN fitting data distribution can capture the time-varying and multipath characteristics of the channel well. Considering the propagation characteristics of real channel, we further develop a channel prediction error indicator to determine whether the generator reaches the best state. Simulations show that the CPcGAN can obtain higher prediction accuracy and lower system bit error rate than the existing methods under the same user speeds.

关键词： channel prediction time-varying channel conditional generative adversarial network multipath channel deep learning

Exponential stability for cellular neural networks: an LMI approach

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Journal of Systems Engineering and Electronics 2007年第1期18卷 68-71页

作者： Liu Deyou zhang jianhua Guan Xinping Coll. of Science Yanshan Univ. Qinhuangdao 066004 E R. China

A new sufficient conditions for the global exponential stability of the equilibrium point for delayed cellular neural networks （DCNNs） is presented. It is shown that the use of a more general type of Lyapunov-Krasovskii function enables the derivation of new results for an exponential stability of the equilibrium point for DCNNs. The results establish a relation between the delay time and the parameters of the network. The results are also compared with one of the most recent results derived in the literature.

关键词： Delayed cellular neural networks LMI Neural networks Exponential stability