Cooperative Covert Communication in Multi-Antenna Broadcast Channels

With the gradual popularization of 5G communications,the application of multi-antenna broadcasting technology has become widespread.Therefore,this study aims to investigate the wireless covert communication in the two-user cooperative multi-antenna broadcast channel.We focus on the issue that the deteriorated reliability and undetectability are mainly affected by the transmission power.To tackle this issue,we design a scheme based on beamforming to increase the reliability and undetectability of wireless covert communication in the multi-antenna broadcast channel.We first modeled and analyzed the cooperative multi-antenna broadcasting system,and put forward the target question.Then we use the SCA(successive convex approximation)algorithm to transform the target problem into a series of convex subproblems.Then the convex problems are solved and the covert channel capacity is calculated.In order to verify the effectiveness of the scheme,we conducted simulation verification.The simulation results show that the proposed beamforming scheme can effectively improve the reliability and undetectability of covert communication in multi-antenna broadcast channels.

A Deep Learning Based Broadcast Approach for Image Semantic Communication over Fading Channels

We consider an image semantic communication system in a time-varying fading Gaussian MIMO channel,with a finite number of channel states.A deep learning-aided broadcast approach scheme is proposed to benefit the adaptive semantic transmission in terms of different channel states.We combine the classic broadcast approach with the image transformer to implement this adaptive joint source and channel coding(JSCC)scheme.Specifically,we utilize the neural network(NN)to jointly optimize the hierarchical image compression and superposition code mapping within this scheme.The learned transformers and codebooks allow recovering of the image with an adaptive quality and low error rate at the receiver side,in each channel state.The simulation results exhibit our proposed scheme can dynamically adapt the coding to the current channel state and outperform some existing intelligent schemes with the fixed coding block.

A novel multi-channel porous structure facilitating mass transport towards highly efficient alkaline water electrolysis

An advantageous porous architecture of electrodes is pivotal in significantly enhancing alkaline water electrolysis(AWE)efficiency by optimizing the mass transport mechanisms.This effect becomes even more pronounced when aiming to achieve elevated current densities.Herein,we employed a rapid and scalable laser texturing process to craft novel multi-channel porous electrodes.Particularly,the obtained electrodes exhibit the lowest Tafel slope of 79 mV dec^(-1)(HER)and 49 mV dec^(-1)(OER).As anticipated,the alkaline electrolyzer(AEL)cell incorporating multi-channel porous electrodes(NP-LT30)exhibited a remarkable improvement in cell efficiency,with voltage drops(from 2.28 to 1.97 V)exceeding 300 mV under 1 A cm^(-1),compared to conventional perforated Ni plate electrodes.This enhancement mainly stemmed from the employed multi-channel porous structure,facilitating mass transport and bubble dynamics through an innovative convection mode,surpassing the traditional convection mode.Furthermore,the NP-LT30-based AEL cell demonstrated exceptional durability for 300 h under 1.0 A cm^(-2).This study underscores the capability of the novel multi-channel porous electrodes to expedite mass transport in practical AWE applications.

Design of Cold-Junction Compensation and Disconnection Detection Circuits of Various Thermocouples and Implementation of Multi-Channel Interfaces Using Them-A Secondary Publication

Cold-junction compensation(CJC)and disconnection detection circuit design of various thermocouples(TC)and multi-channel TC interface circuits were designed.The CJC and disconnection detection circuit consists of a CJC semiconductor device,an instrumentation amplifier(IA),two resistors,and a diode for disconnection detection.Based on the basic circuit,a multi-channel interface circuit was also implemented.The CJC was implemented using compensation semiconductor and IA,and disconnection detection was detected by using two resistors and a diode so that IA input voltage became-0.42 V.As a result of the experiment using R-type TC,the error of the designed circuit was reduced from 0.14 mV to 3μV after CJC in the temperature range of 0°C to 1400°C.In addition,it was confirmed that the output voltage of IA was saturated from 88 mV to-14.2 V when TC was disconnected from normal.The output voltage of the designed circuit was 0 V to 10 V in the temperature range of 0°C to 1400°C.The results of the 4-channel interface experiment using R-type TC were almost identical to the CJC and disconnection detection results for each channel.The implemented multi-channel interface has a feature that can be applied equally to E,J,K,T,R,and S-type TCs by changing the terminals of CJC semiconductor devices and adjusting the IA gain.

All-Optical Wavelength Conversion With Multi-Channel Broadcasting at 10 Gb/s Using an Electroabsorption Modulator

All-optical wavelength conversion has been demonstrated with an electroabsorption modulator based on cross-absorption modulation. For the first time, simultaneous broadcasting up to 6 different wavelengths at 10Gb/s is obtained with less than 0.5-dB polarization dependence.

Multi-channel terahertz focused beam generator based on shared-aperture metasurface

Most of existing metasurfaces usually have limited channel behavior,which seriouslyhinders their development and application.In this paper,we propose a multi-channel terahertz focused beam generator based on shared-aperture metasurface,and the generator consists of a top square metal strip,a middle layer of silica and a metal bottom plate.By changing the position and size of the shared-aperture array,the designed metasurface can generate any number of multi-channel focusing beams at different predicted positions.In addition,the energy intensity of focusing beams can be controlled.The full-wave simulation results show that the metasurface achieves four-channel vortex focused beam generation with different topological charges,and five-,six-,eight-channel focused beam generation with different energy intensities at a frequency of 1 THz,which are in good agreement with the theoretically calculated predictions.This work can provide a new idea for designing the terahertz multichannel devices.

Fast pre-stack multi-channel inversion constrained by seismic reflection features

Classical multi-channel technology can significantly reduce the pre-stack seismic inversion uncertainty, especially for complex geology such as high dipping structures. However, due to the consideration of complex structure or reflection features, the existing multi-channel inversion methods have to adopt the highly time-consuming strategy of arranging seismic data trace-by-trace, limiting its wide application in pre-stack inversion. A fast pre-stack multi-channel inversion constrained by seismic reflection features has been proposed to address this issue. The key to our method is to re-characterize the reflection features to directly constrain the pre-stack inversion through a Hadamard product operator without rearranging the seismic data. The seismic reflection features can reflect the distribution of the stratum reflection interface, and we obtained them from the post-stack profile by searching the shortest local Euclidean distance between adjacent seismic traces. Instead of directly constructing a large-size reflection features constraint operator advocated by the conventional methods, through decomposing the reflection features along the vertical and horizontal direction at a particular sampling point, we have constructed a computationally well-behaved constraint operator represented by the vertical and horizontal partial derivatives. Based on the Alternating Direction Method of Multipliers (ADMM) optimization, we have derived a fast algorithm for solving the objective function, including Hadamard product operators. Compared with the conventional reflection features constrained inversion, the proposed method is more efficient and accurate, proved on the Overthrust model and a field data set.

Opportunistic Routing with Multi-Channel Cooperative Neighbour Discovery

Due to the scattered nature of the network,data transmission in a dis-tributed Mobile Ad-hoc Network(MANET)consumes more energy resources(ER)than in a centralized network,resulting in a shorter network lifespan(NL).As a result,we build an Enhanced Opportunistic Routing(EORP)protocol architecture in order to address the issues raised before.This proposed routing protocol goal is to manage the routing cost by employing power,load,and delay to manage the routing energy consumption based on theflooding of control pack-ets from the target node.According to the goal of the proposed protocol techni-que,it is possible to manage the routing cost by applying power,load,and delay.The proposed technique also manage the routing energy consumption based on theflooding of control packets from the destination node in order to reduce the routing cost.Control packet exchange between the target and all the nodes,on the other hand,is capable of having an influence on the overall efficiency of the system.The EORP protocol and the Multi-channel Cooperative Neighbour Discovery(MCCND)protocol have been designed to detect the cooperative adja-cent nodes for each node in the routing route as part of the routing path discovery process,which occurs during control packet transmission.While control packet transmission is taking place during the routing path discovery process,the EORP protocol and the Multi-channel Cooperative Neighbour Discovery(MCCND)protocol have been designed to detect the cooperative adjacent nodes for each node in the routing.Also included is a simulation of these protocols in order to evaluate their performance across a wide range of packet speeds using Constant Bit Rate(CBR).When the packet rate of the CBR is 20 packets per second,the results reveal that the EORP-MCCND is 0.6 s quicker than the state-of-the-art protocols,according to thefindings.Assuming that the CBR packet rate is 20 packets per second,the EORP-MCCND achieves 0.6 s of End 2 End Delay,0.05 s of Routing Overhead Delay,120 s of Network Lifetime,and 20 J of Energy Consumption efficiency,which is much better than that of the state-of-the-art protocols.

The National Formation of the Right to Health:Taking Broadcast Gymnastics as an Example

Broadcast gymnastics,which was initiated in 1951,is one of the most widely adopted and popular mass sports activities in China,embodying the country's commitment to shaping the right to health of its citizens.The history and development of broadcast gymnastics are closely tied to the destiny of the nation,reflecting clear national will,and aiming to achieve the goal of“shaping new individuals”.The institutional forms of broadcast gymnastics can be categorized into three stages:“military simulation”,“administrative reinforcement”and“market competition”,each of which aligns with the objectives and needs of different periods.Taking the establishment and promotion of broadcast gymnastics in China as a focal point helps construct a doctrinal framework for the right to health.Based on the purposes and means of health shaping,the implementation of the right to health can be divided into four types:national health projects,citizens'health rights,the social health industry,and civic health consumption.National health projects,facilitated by legislative mechanisms,provide institutional support and supply for citizens'health rights.The right to health,as a social right,has both a subjective rights orientation and an objective value order orientation,thus establishing the individual's subject status in terms of their right to health.Its defense aspect is oriented toward rejecting excessive state intervention,while the benefit aspect directly links to the state's payment measures.The boundaries of state power also need to be defined in the social health industry and civic health consumption.Hence,developing broadcast gymnastics involves adjusting its relationship with the overall objectives of the state and individual citizens'needs.It involves balancing the use of administrative and market methods,continually innovating sports programs that better suit diverse needs,and actively participating in the competition of the fitness market.

直播电商背景下国货品牌崛起的演化机制研究

借助直播平台优势,通过政府扶持,实现国货品牌崛起,在当前经济形势下成为大势所趋。考虑政府、直播电商平台和国货品牌方的有限理性,构建三方演化博弈模型,研究不同环境条件下各博弈主体的策略选择。分析结果表明:在直播电商行业发展的不同阶段,直播电商平台和政府部门的策略选择不同,在直播电商行业发展初期,直播平台违规经营动机强烈,政府创新监管动力不足,国货品牌难以突破发展瓶颈;而在条件成熟时,政府和平台合力支持国货品牌发展,实现国货品牌崛起。

电商直播中消费者购买意愿影响因素研究——基于双路径模型视角

随着电商直播步入新的风口,其蕴藏的巨大商业潜力受到越来越广泛的关注,消费者购买意愿成为影响电商直播可持续发展的重要因素。研究运用双路径模型(ELM),基于中枢路径和边缘路径构建消费者购买意愿的影响因素,实证分析在电商直播中产品因素与主播特征对消费者购买意愿的影响。研究发现,产品质量、价格优惠性、主播吸引力和主播交互性对购买意愿有显著正向影响,但主播专业性对购买意愿的影响并不显著;在中枢路径下,产品质量和价格优惠性通过实用价值影响消费者购买意愿;在边缘路径下,主播专业性、主播吸引力和主播交互性通过享乐价值影响消费者购买意愿。

融媒体时代直播电商经济发展问题分析

本文着眼于融媒体时代直播电商经济发展,旨在探究融媒体时代直播电商经济发展中存在的问题与有效解决路径。首先,文章从介绍融媒体时代的定义和特征、直播电商发展和趋势及融媒体时代对直播电商经济发展的影响入手,阐述研究的必要性和可行性;其次,分析直播电商经济发展中存在的问题,包括直播电商平台的数量和竞争激烈性、直播电商产品质量和消费者权益保护、直播电商购物体验和社交互动的平衡三方面内容,并针对直播电商经济发展中存在的问题提出相应的意见和建议,以供参考。

基于数据传输特性的卫星广播通道参数优化方法与应用

中国气象局卫星广播系统(CMACast)是全球对地观测广播系统(GEONETCast)框架下三大对地广播系统之一,在世界气象组织信息系统(WIS)和综合卫星数据分发服务系统(IGDDS)框架下,承担亚太地区气象数据广播分发的职责。随着气象业务的发展,广播系统数据量由180 GB/天增长至460 GB/天,在广播带宽资源有限而广播数据种类和大小各异的情况下,系统管理员越来越难以通过经验对广播通道参数调整以保持广播系统播发效率,造成部分通道数据播发时效下降严重,不能满足业务时效要求。通过对不同气象数据传输特性的定量分析,获得各类数据的精细化数据传输样本,在此基础上对各类数据广播通道参数进行科学、定量的计算和优化,使数据播发时效明显提升,应用到实际广播业务中效果明显。

基于广电5G 的体育直播类高新视频技术方案研究

首先介绍高新视频的定义,提出基于5G网络传输的高新视频在体育直播类业务中的应用场景。其次阐述体育直播类高新视频业务对传输网络的需求,对广电5G网络能力进行分析,包括空口速率、网络时延及可靠性等内容。最后提出基于广电5G的体育直播类高新视频技术方案,包括总体技术架构及相关功能模块等内容,为广电行业探索高新视频应用创新提供参考。

利用MQTT通信实现图像广播功能

图像广播功能不仅可以降低项目建设成本,而且能够提高图像采集设备的利用效率。为有效解除应用程序耦合及简化代码复杂度,本文提出一种基于MQTT通信的图像广播功能的方案。该系统采用EMQX软件搭建MQTT服务端,使用paho-mqtt客户端库创建客户端应用程序,并采用BASE64对图像进行编解码。测试结果表明,该图像广播系统基本达到了设计要求。

ARP协议仿真实验设计与实现

ARP协议是TCP/IP协议栈中重要的协议之一,掌握其工作原理对于理解局域网底层通信逻辑至关重要。文章不仅分析了同网段通信时ARP协议的工作原理,而且还分析了跨网段通信时ARP协议的工作原理,并给出了相关仿真实验过程。研究对于更好地理解和掌握ARP协议,解决在现实中遇到的网络问题具有实践指导意义。

GNSS卫星轨道机动探测技术进展

针对轨道机动探测是各种空间任务的共性关键技术,是全球卫星导航系统(GNSS)精密定轨定位数据处理的首要工作,在卫星导航领域具有重要的研究意义,尤其是中国多星座构型的北斗卫星导航系统,轨道机动频繁,影响更为严重的现状,研究分析全球卫星导航系统(GNSS)卫星轨道机动探测技术的进展:概述轨道机动的概念、机动方式和机动时间;归纳整理目前GNSS卫星轨道机动探测中常用的技术方法,包括基于卫星轨道的探测方法、基于卫星广播星历的探测方法以及基于观测值的探测方法;总结各类卫星轨道机动探测方法的特点,并统计分析GNSS卫星的轨道机动频次与时段,指出随着GNSS卫星轨道机动探测方法的不断完善,实时及事后卫星轨道机动探测问题都得到了显著改善,促进了GNSS服务性能的进一步提升;最后,总结现有轨道机动探测方法的优势与局限性,展望GNSS轨道机动卫星数据处理中尚须进一步解决的重要问题。

直播平台内观众与主播间法律关系的性质研究

直播打赏关系的性质界定对消费者权益保护与纠纷预防具有重大意义。直播打赏关系中虚拟货币的转移作为实质上的财产转移值得法律评价和规范,该关系完全符合合同成立的要件,应被认定为独立的合同关系。直播打赏基本运行模式为“非强制性付费”商业模式,基于对主播与观众之间真实意思表示的尊重,直播打赏合同不宜被认定为赠与合同,而应是网络服务合同。相较于平台和观众之间的网络服务合同,直播打赏网络服务合同在格式、主体、权利义务、履行等方面具有特殊性,可以考虑引入打赏冷静期作为配套措施,但在其具体规则的设计上应注重规制消费者的“恶意反悔”。同时,直播平台作为网络服务交易平台提供者,在不能提供主播的有效联系方式时,应当依据《消费者权益保护法》规定,承担对消费者的先行赔偿责任,以辅助相关纠纷的妥善化解。

从内容为王到解说为王——对电视与新媒体直转播北京冬奥会的流量之争的思考

北京2022年冬奥会期间不仅有运动员在赛场上争分夺秒、你追我赶的角逐,而且竞技场外的“第二赛场”——媒体流量之争同样激烈。“内容为王”是媒体行业提升传播力的重要途径。越来越多的现象表明,赛事直转播内容中的体育解说的价值正在逐渐被放大。运用文献研究法、录像分析法、案例分析法、专家访谈法等方法,以央视体育频道和咪咕视频为例,分析两者在北京2022年冬奥会期间赛事解说的特点、优势与不足,探讨北京冬奥会赛事直转播的流量之争,并引发了相关思考。北京2022年冬奥会的体育解说屡屡出现在互联网热搜榜,在这场新媒体与传统媒体的对比中体现了咪咕视频赛事解说的创新与央视体育频道赛事解说的求稳。经过研究得出如下结论:在后冬奥时期,咪咕视频应持续供给优质内容;央视体育频道要适度创新;体育解说与人工智能深度融合可以实现差异化竞争;兼顾高度与温度,实现体育赛事的亲民化传播;加强“大屏幕”与“小屏幕”的联动,增强解说员的个性特色;解说立场应不偏不倚,并且要彰显包容姿态。

人工智能技术在广播电视行业的应用研究

在智能媒介的浪潮中,广播电视行业正在经历一场前所未有的变革。人工智能、通信、物联网等尖端技术的融合,为广播电视行业注入新的活力。概述人工智能技术的概念,分析人工智能技术在广播电视行业中应用的技术优势,从内容生产、视听服务、数智应用、安全发展4个方面进行应用分析,提出人工智能在广播电视行业的发展方向。