A Predictive 6G Network with Environment Sensing Enhancement:From Radio Wave Propagation Perspective

In order to support the future digital society,sixth generation(6G)network faces the challenge to work efficiently and flexibly in a wider range of scenarios.The traditional way of system design is to sequentially get the electromagnetic wave propagation model of typical scenarios firstly and then do the network design by simulation offline,which obviously leads to a 6G network lacking of adaptation to dynamic environments.Recently,with the aid of sensing enhancement,more environment information can be obtained.Based on this,from radio wave propagation perspective,we propose a predictive 6G network with environment sensing enhancement,the electromagnetic wave propagation characteristics prediction enabled network(EWave Net),to further release the potential of 6G.To this end,a prediction plane is created to sense,predict and utilize the physical environment information in EWave Net to realize the electromagnetic wave propagation characteristics prediction timely.A two-level closed feedback workflow is also designed to enhance the sensing and prediction ability for EWave Net.Several promising application cases of EWave Net are analyzed and the open issues to achieve this goal are addressed finally.

Physical properties of relativistic electron beam during long-range propagation in space plasma environment

It is known that ion channel can effectively limit the radial expansion of an artificial electron beam during its longrange propagation in the space plasma environment.Most prior studies discussed the focusing characteristics of the beam in the ion channel,but the establishment process and transient properties of the ion channel itself,which also plays a crucial role during the propagation of the relativistic electron beam in the plasma environment,were commonly neglected.In this study,a series of two-dimensional(2D)particle-in-cell simulations is performed and an analytical model of ion channel oscillation is constructed according to the single-particle motion.The results showed that when the beam density is higher than the density of plasma environment,ion channel can be established and always continues to oscillate periodically over the entire propagation.Multiple factors,including the beam electron density,initial beam radius,and the plasma density can affect the oscillation properties of ion channel.Axial velocity of the beam oscillates synchronously with the ion channel and this phenomenon will finally develop into a two-stream instability which can seriously affect the effective transport for relativistic electron beam.Choosing appropriate beam parameters based on various plasma environments may contribute to the improvement of the stability of ion channel.Additionally,radial expansion of the beam can be limited by ion channel and a stable long-range propagation in terrestrial atmosphere may be achieved.

Environment Information-Based Channel Prediction Method Assisted by Graph Neural Network

Recently,whether the channel prediction can be achieved in diverse communication scenarios by directly utilizing the environment information gained lots of attention due to the environment impacting the propagation characteristics of the wireless channel.This paper presents an environment information-based channel prediction(EICP)method for connecting the environment with the channel assisted by the graph neural networks(GNN).Firstly,the effective scatterers(ESs)producing paths and the primary scatterers(PSs)generating single propagation paths are detected by building the scatterercentered communication environment graphs(SCCEGs),which can simultaneously preserve the structure information and highlight the pending scatterer.The GNN-based classification model is implemented to distinguish ESs and PSs from other scatterers.Secondly,large-scale parameters(LSP)and small-scale parameters(SSP)are predicted by employing the GNNs with multi-target architecture and the graphs of detected ESs and PSs.Simulation results show that the average normalized mean squared error(NMSE)of LSP and SSP predictions are 0.12 and 0.008,which outperforms the methods of linear data learning.

Wave Motion of Smoke in Subway Fire Environment

Wave motion in subway or tunnel fire is an intrinsic property of smoke.As the pressure of smoke changes with mass of certain power,a kind of linear wave equation for smoke can be derived from the conservation equations of its mass and momentum,under nearly homogeneous zone assumption.The smoke movement of 4 subway fires was simulated with Airpak.By fitting the pressure-mass functions to the simulated data,wave equations of the smoke were derived,and wave motions of smoke were thus validated.It can be seen that smoke wave is a kind of mass wave,whose velocity is inversely proportional to smoke mass,and wave of a bigger fire propagates slower.

电大山区地物环境中电波传播的电磁计算

在无人驾驶与无人机等新兴行业中,信号覆盖范围的要求较高,不仅仅在城市,在人迹罕至的山地、沙漠、森林中也需要无线信号的覆盖才能真正完成远程操控,这些地区更多需要考虑的是地势变化对电磁传播所带来的影响。计算电磁学中的一致性几何绕射理论方法是分析电大环境电磁问题的有效方法,使用计算电磁学的方法研究电磁波在山区地物环境中的传播规律。给出了一种建立不规则地形模型的新方法,可以通过数字高程的网格数据生成电磁算法可用的三次多项式曲面,使用多个立方曲面对不规则地形进行拼接,使用平均均方根误差验证模型数据的准确性。基于所得的地形数据,完成了并行的几何光学算法,并对区域电磁场的分布进行了仿真计算。选取了实际山区地物环境进行了实地测量,测量结果与仿真结果对比趋势一致,验证了该方法在非规则地形中电磁波传播分析中的有效性。考虑环境电磁计算的规模,建立了相应的并行策略,100核测试的并行效率可以保持在80%以上。

新媒体环境下高校思政教育碎片化传播效应研究

针对新媒体环境下思政教育传播效应问题,采用归纳分析的方法,分析了新媒体环境下高校思政教育信息传播的主要特征以及内在要求,对新媒体环境下高校思政教育碎片化传播的正向影响和负向影响进行探讨,提出革新教学理念,强化思政课教师新媒体环境下的信息化教学素养;重构碎片化传播下的高校思政教育话语体系;秉承以学生为本,碎片化教育传播精准对接学生学习需求;完善新媒体环境下“互联网+思政”教学体系评价机制等策略,为推动新时期高校思政教育创新发展提供参考。

寒区电动公交充电站选址及定容规划研究

寒区低温环境导致电动公交动力电池容量衰减,充电设施服务范围及规划数量受到影响,给电动公交充电站选址及定容规划带来挑战。为提高电动公交充电站的低温适应性,提出针对寒区电动公交充电站的选址算法及定容模型。首先,在选址规划中,构建充电站渐进覆盖服务半径,利用改进近邻传播聚类算法确定充电站选址点,基于算法聚类中心构建充电站Voronoi图划分充电集群。其次,在定容规划中,构建动力电池低温容量衰减模型,确定寒区电动公交的充电需求;基于容量有限的截尾排队论模型建立充电站有效服务强度、拒绝服务率及充电满意度等约束;引入成本权衡系数,以规划年限内全社会成本最小为优化目标,建立寒区充电站定容规划模型,并设计遗传算法进行求解。最后,以哈尔滨市市区电动公交充电站选址定容规划为例进行分析,算例结果得到9个充电站选址点及其充电集群,以及各充电站的充电机配置数量和各项成本。针对环境温度和成本权衡系数进行灵敏度分析,结果表明:寒区低温环境对充电站的充电机配置数量和各项成本有显著影响,合理权衡充电站和电动公交两者利益有助于提高充电服务满意度,降低全社会成本。

基于DNN的二维抛物方程电波传播修正模型

针对二维抛物方程(Two-dimensional Parabolic Equation,2DPE)只能对二维通信链路进行建模,无法计算电磁波在城市环境下对建筑物的横向绕射和后向反射效应的缺陷,提出一种基于深度神经网络(Deep Neural Network,DNN)的2DPE修正模型。通过数字高程地图建立城市建筑物三维模型,提取出传播距离、传播角度和建筑覆盖率等7个特征,对传播路径上的建筑物分布和收发天线的部署情况进行表征。结合实测数据,构建用于修正2DPE的数据集;通过DNN进行训练,构建2DPE的修正模型,使其适用于复杂三维环境下的电波传播预测。仿真结果表明,相比于线性回归、支持向量回归和决策树模型,基于DNN的2DPE修正模型在三维传播环境中计算精度高,在测试集上的预测误差最多降低了46.8%。

Novel Sum-of-Sinusoids Simulation Channel Modeling for 6G Multiple-Input Multiple-Output Vehicle-to-Everything Communications

In this paper,a statistical cluster-based simulation channel model with a finite number of sinusoids is proposed for depicting the multiple-input multiple-output(MIMO)communications in vehicleto-everything(V2X)environments.In the proposed sum-of-sinusoids(SoS)channel model,the waves that emerge from the transmitter undergo line-of-sight(LoS)and non-line-of-sight(NLoS)propagation to the receiver,which makes the model suitable for describing numerous V2X wireless communication scenarios for sixth-generation(6G).We derive expressions for the real and imaginary parts of the complex channel impulse response(CIR),which characterize the physical propagation characteristics of V2X wireless channels.The statistical properties of the real and imaginary parts of the complex CIRs,i.e.,autocorrelation functions(ACFs),Doppler power spectral densities(PSDs),cross-correlation functions(CCFs),and variances of ACFs and CCFs,are derived and discussed.Simulation results are generated and match those predicted by the underlying theory,demonstrating the accuracy of our derivation and analysis.The proposed framework and underlying theory arise as an efficient tool to investigate the statistical properties of 6G MIMO V2X communication systems.

基于射线追踪的微蜂窝环境内组合位置无线信号特性研究

为了提高频谱利用率及减少传播过程的能量衰减,建立高效的信号传播模型来预测传播路径和接收处信号强度有着重要意义。针对微蜂窝环境,提出入射及反弹射线法建立二维射线追踪模型,并基于此分析该环境下不同发射-接收机组合的信号传播特性。结果表明:不同组合的距离和微蜂窝环境共同影响信号传播路径数量。距离接近并且拥有较好的反射环境的组合的传播路径数量更多,信号损失更少。研究成果能够为微蜂窝环境下的网络规划建设提供指导。

PROPAGATION OF INTERNAL INERTIO-GRAVITY WAVE SPECTRA IN VERTICAL WIND SHEAR ENVIRONMENTS

The variation of the spectral structure of the internal inertio-gravity waves (ⅡGWs) propagating in the atmospheric wind shear environments is discussed in this paper. From the hydrodynamic equation set in Boussinesq approximation, a spectral propagation equation ⅡGWs satisfy is derived, then the spectral correspondence in the upper atmosphere is numerically calculated, after a forced spectrum is given as a Van- Zandt one at the lower boundary. The results show that if ⅡGWs do not encounter the critical-layer absorp- tion, then their spectral structure may be not changed significantly; otherwise it may be changed greatly, and a few of spectral components are filtered. Also the isotropy of the assumed VanZandt spectrum is distorted in upward-propagating process. That is the directional filtering effect of the atmospheric wind on the gravity wave spectrum.

对流层大气波导超视距传播技术研究与展望

全面介绍了中国电波传播研究所建所60年来,在对流层大气波导超视距电波环境及传播专业领域的研究及其应用情况,主要包括对流层大气波导机理与预测模型研究、大气波导探测感知与预测预报方法、超短波/微波超视距传播算法、无线电信息化系统装备超视距验证评估及信息保障等反映该领域国内相关技术的发展历程和最新研究成果,并结合实际应用需求提出了未来技术的发展趋势.

城市拥塞环境下交通事故风险传播及控制研究

为了解城市拥塞环境下交通事故风险因子间的逻辑相互作用以及事故风险传播,提升拥塞环境下风险控制能力,依据拥塞实际调查数据,首先对交通拥塞环境下的事故风险形成及传播过程机理进行分析,以交通冲突量化事故风险水平,标定对于每次交通冲突起绝对作用的一个或几个风险因子。基于复杂网络理论,最终筛选35个风险因子作为网络节点,将拥塞环境形成到消散过程分为9个时间区间,构造风险时间序列,应用Pearson相关性和Granger因果检验相结合的方法构建交通事故风险传播有向网络;引入节点重要度Ki概念,对选取的可人为干预节点改进感染率β′和恢复率λ′,构建一种适用于城市拥塞环境下交通事故风险传播的改进SIR模型。结果表明,对中央分隔带设置、交通信息发布、路面状况、驾驶员路内不规范停车风险节点控制后,感染节点峰值下降23.37%;对考虑节点重要度Ki的4个风险节点控制后,感染节点峰值下降达43.43%,交通事故风险传播规模抑制明显。

基于FIO-COM的海洋声学预报系统的构建与应用

将海洋模式与声传播模型结合在一起,设计开发了一种适用于高性能计算机的全球海洋声学预报系统FIO-GOAFS,该系统以自然资源部第一海洋研究所全球0.1°分辨率海浪-潮流-环流耦合模式(FIOCOM)为基础,利用海洋模式预报的温、盐、深参数计算声速剖面,并对声速剖面进行水声环境特征诊断,之后将海洋模式与水下声场传播模型协同连接,结合地声模型(海底地形和底质参数),实现了全球海域的水声环境特征诊断及水下声场及相关结果的预报。海洋模型提供水下声学预报所需的水体声速、海浪波高等参数,地声模型提供海底地形、底质声速、密度以及衰减等参数,通过调用海洋-声学连接模块提取声传播路径的地形及海洋环境参数剖面,实现海洋模型和声学模型的有效连接。全球海洋声学预报系统在高性能计算机上并行实现,主要包括声场计算中的频点、方位角并行以及声学预报时针对地理空间区域的并行。最后,利用该系统预报并分析了全球海域的水声环境特性及声呐作用距离的季节变化和空间分布特征,为现代声呐的设计、操作和水下应用提供参考。

抛物方程法预测复杂地海环境中的电波传播

为了分析对流层环境中影响电波传播的主要因素,文章基于抛物方程模型研究了复杂地海环境下的电波传播特性,综合考虑粗糙海面Miller-Brown近似、地形遮蔽法、分段线性平移变换法等处理方法,分析了海上岛屿、沿海城市、蒸发波导、发射天线参数、风速等因素对电波传播造成的影响。结果表明,电波传播损耗受蒸发波导、海岛高度和频率的影响较大,而远距离传播时受海面风速的影响较小,海岛的存在会使电波产生多径效应,而其遮蔽效应也会令传播损耗有所增加。此外,近海岸的地理环境同样对传播损耗的影响较大,而随着高度的增加,这种影响逐渐减小,因此,提高发射天线的高度可以有效延长探测距离。这些结果对雷达系统的设计和性能评估具有重要的指导意义。

降雨环境下电磁波短距离传播衰减研究

随着无线电技术的不断革新,在降雨等复杂环境下由于电磁波传播特性变化造成对武器系统的影响逐步被重视。与以往降雨环境下的远距离电磁波传播研究不同,着重阐述了近距离传播过程中电磁波的衰减问题。通过电磁仿真软件的帮助,根据层状云降水情况建立仿真模型,模拟多个频段下电磁波短距离传播过程,并通过计算路径前后电磁波能量差值以反映出电磁波衰减情况。结果表明,在降雨环境中,短距离的电磁波传播由于雨滴的影响,存在较大的衰减,随着频率和传播距离的增加,电磁波的衰减也在增加。

多语言环境下具有惩罚机制和时滞的谣言传播动力学研究

提出了一种多语言环境下带有惩罚机制和时滞的谣言传播优化控制模型.首先,通过分析平均场方程推导出模型的基本再生数R0.其次,基于Routh-Hurwitz判据、Lyapunov方法和LaSalle不变原理,研究了无谣言/谣言盛行平衡点的存在性和稳定性.同时,为了有效地控制谣言传播和控制成本,提出了带有惩罚机制的最优控制.最后,通过数值模拟验证了理论结果的有效性.

MicroAFL:一种云上微服务故障自动定位方法

随着云上微服务系统规模的不断扩大,微服务之间的依赖关系变得更加紧密复杂,某个微服务的故障可能会通过微服务之间的互相调用传播至其他微服务,进而导致整个微服务系统发生异常。面对依赖关系复杂的微服务系统,考虑到故障的传播性,设计了一种云上微服务故障自动定位方法MicroAFL。首先,MicroAFL实时监测与收集微服务系统运行指标数据,基于自编码器模型对运行指标数据进行分析,判断微服务系统是否存在异常;一旦检测到异常,MicroAFL通过解析云上微服务运行实例之间的通讯数据获取微服务之间的调用关系,进而构建服务调用关系图以刻画故障传播途径;其次,将各个微服务的运行状态与系统资源利用率相关联从而计算服务调用关系图中每个节点的异常权重,并通过改进的加权PageRank算法推断和定位引发异常的故障微服务;最后,在华为云上搭建名为Sock-shop的微服务系统对MicroAFL的故障定位准确性进行评估,实验结果表明MicroAFL的故障定位准确率相较对比方法有所提升。

低温环境下TC4ELI钛合金三维疲劳裂纹扩展模型

利用疲劳试验机及扫描电镜研究了不同温度(20,-20,-40,-60℃)下不同厚度(12.5,9.0,6.0,3.0 mm)TC4ELI钛合金的疲劳裂纹扩展行为,建立低温环境下该合金的三维疲劳裂纹扩展模型。结果表明:由于闭合效应,减小厚度或降低温度均会减缓试验合金的疲劳裂纹扩展速率,Paris二维公式中的材料参数C和n并非常数;而在三维疲劳裂纹扩展理论框架下,修正后的Paris三维公式中的材料参数C_(eff)和n_(eff)均为常数,建立的三维疲劳裂纹扩展模型可以对不同温度下不同厚度试验合金的疲劳裂纹扩展行为进行归一化描述。

考虑学习效率的教室内热环境调控系统研究

教室环境对学生的舒适程度和学习效率有直接影响,因此如何对其进行调控非常重要。针对现有室内调控方案未考虑学习效率的问题,在确定热舒适度与学习效率量化关系的情况下,提出一套针对教室的室内热环境调控系统。将学习效率最高时的预测平均投票值(predicted mean vote,PMV)作为系统的目标,为实时获取PMV提出了基于粒子群优化的BPNN(back propagation neural network)模型对其进行预测的方法,通过PMV反推出热环境参数(温度、风速和相对湿度)的目标值,并提出基于BPNN的比例积分微分(proportion integration differentiation,PID)控制器对其进行调控以改变室内热环境。通过实地采集的数据对调控系统进行仿真模拟,结果证明了调控系统的可行性和有效性,为积极推进教室内热环境的调控提供了有效依据。