期刊文献+
共找到4,695篇文章
< 1 2 235 >
每页显示 20 50 100
Design Method for Optimizing the Interactive Interface of Live Broadcasting Platform for the Elderly Users
1
作者 WEI Bi-ze FAN Wei DUAN Ying-ke 《印刷与数字媒体技术研究》 CAS 北大核心 2024年第4期167-178,共12页
In the era of network live broadcasting for everyone,the development of live broadcasting platforms is also more intelligent and diversified.However,in the face of a large group of elderly users,the interface interact... In the era of network live broadcasting for everyone,the development of live broadcasting platforms is also more intelligent and diversified.However,in the face of a large group of elderly users,the interface interaction design mode used is still mainly based on the interaction mode for young groups,and is not designed for elderly users.Therefore,a design method for optimizing the interaction interface of live broadcasting platform for elderly users was proposed in this study.Firstly,the case study method and Delphi expert survey method were used to determine the design needs of elderly users and the design mode was analysed.Secondly,the orthogonal design principle was used to design a test sample of the interactive interface of live broadcasting platform applicable for the elderly users,and then a user evaluation system was established to calculate the weights of the design elements using hierarchical analysis,and then the predictive relationship between the design mode of the interactive interface of live broadcasting platform and the elderly users was established by Quantitative Theory I.Finally,Genetic Algorithm was applied to generate the optimized design scheme.The results showed that the design method based on the Genetic Algorithm and the combination of Quantitative Theory can scientifically and effectively optimize the design of the interactive interface of the live broadcasting platform for the elderly users,and improve the experience of the elderly users. 展开更多
关键词 Live broadcasting platform Interaction design Elderly users Genetic Algorithm Quantitative Theory I
在线阅读 下载PDF
Broadcasting with Controlled Redundancy and Improved Localization in Wireless Sensor Networks 被引量:2
2
作者 Tarun Dubey Om Prakash Sahu 《Journal of Electronic Science and Technology》 CAS 2013年第4期404-407,共4页
Wireless sensor networks (WSNs) consist of sensor nodes that broadcast a message within a network. Efficient broadcasting is a key requirement in sensor networks and has been a focal point of research over the last ... Wireless sensor networks (WSNs) consist of sensor nodes that broadcast a message within a network. Efficient broadcasting is a key requirement in sensor networks and has been a focal point of research over the last few years. There are many challenging tasks in the network, including redundancy control and sensor node localization that mainly depend on broadcasting. In this paper, we propose a broadcasting algorithm to control redundancy and improve localization (BACRIL) in WSNs. The proposed algorithm incorporates the benefits of the gossip protocol for optimizing message broadcasting within the network. Simulation results show a controlled level of redundancy, which is up to 57.6% if the number of sensor nodes deployed in a 500 m×500 m area are increased from 50 to 500. 展开更多
关键词 broadcast GOSSIP LOCALIZATION nodedensity REDUNDANCY wireless sensor networks.
在线阅读 下载PDF
Partially secret broadcasting,partially secret splitting with quantum entanglement 被引量:2
3
作者 刘玉 张彬彬 《Chinese Physics B》 SCIE EI CAS CSCD 2010年第1期90-94,共5页
In this paper, we propose a classical secret broadcasting and splitting joint protocol in a quantum scenario. With those genuinely entangled states, the boss can always broadcast some of his secrets and split some oth... In this paper, we propose a classical secret broadcasting and splitting joint protocol in a quantum scenario. With those genuinely entangled states, the boss can always broadcast some of his secrets and split some others to multi- receivers at the same time. The efficiency of the joint protocol is also compared with that of two separate ones which realise classical secret broadcasting and classical secret splitting respectively, and based on the comparison we can see the promising advantage of our joint protocol is that it can realise the two tasks more efficiently and more conveniently. 展开更多
关键词 secret broadcasting secret splitting quantum entanglement
在线阅读 下载PDF
High Robust Broadcasting over DTMB-A with Low-rate LDPC Codes 被引量:2
4
作者 Chao Zhang Kewu Peng +2 位作者 Zhitong He Yonglin Xue Hui Yang 《China Communications》 SCIE CSCD 2022年第3期192-201,共10页
As the 2nd generation digital terrestrial television broadcasting(DTTB)standard,digital terrestrial/television multimedia broadcasting-advanced(DTMB-A)can provide higher spectrum efficiency and transmission reliabilit... As the 2nd generation digital terrestrial television broadcasting(DTTB)standard,digital terrestrial/television multimedia broadcasting-advanced(DTMB-A)can provide higher spectrum efficiency and transmission reliability by adopting flexible frame structure and advanced forward error correction coding compared with the 1 st generation DTTB systems.In order to increase the flexibility and robustness of the DTTB network,the frequency reuse scheme of factor one(reuse-1)is proposed,where the same RF channel is used by different stations covering the adjacent service areas.However,it demands a very low carrier-tonoise ratio(C/N)threshold below 0 dB at the DTTB physical layer.In this paper,a robust broadcasting technique is proposed based on DTMB-A with newly designed low-rate low density parity check(LDPC)codes.By adopting quasi-cyclic(QC)Raptor-like structure and progressive lifting method,the high performance low-rate LDPC codes are designed supporting multiple code lengths.Both density-evolution analyses and laboratory measurements demonstrate that DTMB-A with low-rate coding can complete the demodulation reliably with the C/N threshold below0 d B,which is one important necessary condition to support frequency reuse-1 scheme. 展开更多
关键词 digital terrestrial/television multimedia broadcasting-advanced(DTMB-A) digital terrestrial television broadcasting(DTTB) low-rate low density parity check(LDPC)code
在线阅读 下载PDF
A Deep Learning Based Broadcast Approach for Image Semantic Communication over Fading Channels 被引量:2
5
作者 Ma Kangning Shi Yuxuan +1 位作者 Shao Shuo Tao Meixia 《China Communications》 SCIE CSCD 2024年第7期78-94,共17页
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 adapt... 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. 展开更多
关键词 broadcast approach deep learning fading channels semantic communication
在线阅读 下载PDF
Multi-User Semantic Fusion for Semantic Communications over Degraded Broadcast Channels 被引量:1
6
作者 Wu Tong Chen Zhiyong +2 位作者 Tao Meixia Xia Bin Zhang Wenjun 《China Communications》 SCIE CSCD 2024年第10期86-100,共15页
Degraded broadcast channels(DBC) are a typical multiuser communication scenario, Semantic communications over DBC still lack in-depth research. In this paper, we design a semantic communications approach based on mult... Degraded broadcast channels(DBC) are a typical multiuser communication scenario, Semantic communications over DBC still lack in-depth research. In this paper, we design a semantic communications approach based on multi-user semantic fusion for wireless image transmission over DBC. The transmitter extracts semantic features for two users separately and then effectively fuses them for broadcasting by leveraging semantic similarity. Unlike traditional allocation of time, power, or bandwidth, the semantic fusion scheme can dynamically control the weight of the semantic features of the two users to balance their performance. Considering the different channel state information(CSI) of both users over DBC,a DBC-Aware method is developed that embeds the CSI of both users into the joint source-channel coding encoder and fusion module to adapt to the channel.Experimental results show that the proposed system outperforms the traditional broadcasting schemes. 展开更多
关键词 channel adaptability degraded broadcasting channels semantic communications semantic fusion
在线阅读 下载PDF
Advanced Digital Techniques and Tendencies in the Development of Modem Digital Satellite Broadcasting
7
作者 董荔真 《Journal of Beijing Institute of Technology》 EI CAS 1994年第2期170-175,共6页
The fundamental aspects of digital broadcasting are its service flexibility and power savings, which make all-digital satellite broadcasting a viable and economic propositon compared with analog broadcasting. Tendenci... The fundamental aspects of digital broadcasting are its service flexibility and power savings, which make all-digital satellite broadcasting a viable and economic propositon compared with analog broadcasting. Tendencies in the development of digital television broadcasting are: (1) Stereophonic or two-language sound transmission with television in existing analog TV system, (2) Digital direct satellite broadcasting (D-DBS); (3)Digital high definition television (HDTV) Broadcasting. 展开更多
关键词 satellite broadcasting television high-resolution TV stereophonic technique/ digital Satellite broadcasting
在线阅读 下载PDF
Cooperative DVB-SH Satellite Broadcasting Systems with Rotated Signal Constellations
8
作者 Nikos C.Sagias Stylianos Papaharalabos P.Takis Mathiopoulos 《China Communications》 SCIE CSCD 2015年第6期59-72,共14页
In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) wi... In this paper,we study the advantages of cooperation in broadcasting systems from a geosynchronous earth orbit(GEO)satellite to mobile terminals(MTs),achieved through a terrestrial complementary ground station(CGS) with fixed installment,which acts as a relay.Moreover and in the context of the digital video broadcasting-satellite-to-handheld(DVB-SH) standard,the performance improvements offered by the rotated constellations method are investigated,where prior transmission,a phase rotation of the transmitted symbols by a fixed angle is applied followed by a random component interleaver.Turbo codes with soft decision decoding and appropriate random channel interleavers are also considered.We present analytical expressions for the bit log-likelihood ratios(LLRs)that are needed for soft decision decoding at the MT turbo decoder,while the code combining technique is adapted to improve the end-to-end(E2E) performance.Then,we obtain through extensive computer simulations the average bit error probability(ABEP) of quadrature phase-shift keying(QPSK) signals received over pure land-mobile satellite(LMS)and pure CGS links for coding rates 1/3 and6/7.Moreover,the optimal rotation angles are obtained for both links.E2 E ABEP results are then presented assuming cooperation between GEO and CGS,while the power allocation issue is investigated under fixed total transmission power.Our performance evaluation results show that by using the constellation rotation technique,a performance gain can be achieved for high coding rates. 展开更多
关键词 broadcasting code combining constellation rotation coding rate comple-mentary ground system (CGS) coopera-tion digital video broadcasting satellite-to-hand-held (DVB-SH) DECODE-AND-FORWARD log-likelihood ratio (LLR) quadrature phase-shift keying (QPSK) orthogonal frequency-di-vision multiplexing (OFDM) relays satellitecommunications soft-decision decoding tur-bo codes random interleavers
在线阅读 下载PDF
Cooperative Covert Communication in Multi-Antenna Broadcast Channels
9
作者 Qiao Sen Liu Guangjie +1 位作者 Ji Xiaopeng Liu Weiwei 《China Communications》 SCIE CSCD 2024年第6期246-260,共15页
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... 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. 展开更多
关键词 BEAMFORMING covert communication multi-antenna broadcast channels OFDM
在线阅读 下载PDF
Infinity Broadcasting欲推广可视广播
10
《卫星电视与宽带多媒体》 2005年第9期13-13,共1页
美国广播业巨子Infinity Broadcasting公司日前宣布,将和惠普一起在美国推广普及可视广播。可视广播(Visual Radio)是诺基亚发明的互动的广播技术,芬兰是最早尝试可视广播的国家,英国的维京广播电台年初时也决定将在英国推出这项服... 美国广播业巨子Infinity Broadcasting公司日前宣布,将和惠普一起在美国推广普及可视广播。可视广播(Visual Radio)是诺基亚发明的互动的广播技术,芬兰是最早尝试可视广播的国家,英国的维京广播电台年初时也决定将在英国推出这项服务。通过一款特制的诺基亚手机,听众在收听调频广播节目的同时就可以看到诸如音乐专辑、音乐会的演出时间等相关信息。 展开更多
关键词 INFINITY broadcasting公司 美国 可视广播 手机
在线阅读 下载PDF
China formally issued mobile multimedia broadcasting industry standard
11
《数字通信世界》 2006年第11期93-93,共1页
October 24,2006, China SARFT (State Administration of Radio Film and Television) formally issued the China mobile multimedia broadcasting (namely, Mobile TV) industry standard. The standard is a STiMi standard self-de... October 24,2006, China SARFT (State Administration of Radio Film and Television) formally issued the China mobile multimedia broadcasting (namely, Mobile TV) industry standard. The standard is a STiMi standard self-developed in China and put into practice from No- 展开更多
关键词 MODE WORK NET TV China formally issued mobile multimedia broadcasting industry standard MHZ
在线阅读 下载PDF
基于DVB和IP双结构传输模式的复合流式虚拟视频点播系统设计
12
作者 李玉华 邱心莹 邹璇 《现代电子技术》 北大核心 2025年第4期63-67,共5页
当虚拟视频点播系统遇到高访问量时会使其服务器负荷过大,导致视频传输速度下降、播放不连续。因此,设计一种基于DVB和IP双结构传输模式的复合流式虚拟视频点播系统,以适应用户需求和网络条件,动态调整视频流的传输质量和分辨率。构建基... 当虚拟视频点播系统遇到高访问量时会使其服务器负荷过大,导致视频传输速度下降、播放不连续。因此,设计一种基于DVB和IP双结构传输模式的复合流式虚拟视频点播系统,以适应用户需求和网络条件,动态调整视频流的传输质量和分辨率。构建基于DVB和IP双结构传输模式的复合流式虚拟视频点播系统框架,终端用户通过基础服务层的Web页面提交视频点播申请后,从视频编排层获取点播视频;控制层的播出控制模块调取PBHS算法来实现网络资源受限下的带宽自适应分配,以动态地调整不同带宽占用,优化网络资源利用,提高传输效率。通过视频传送模块输出点播视频,利用传输层的IP和DVB双结构传输模式将其输送到应用层,最终可视化呈现给用户。实验结果表明,所设计系统可实现虚拟视频点播,视频播放连续不卡顿、画面分辨率高,信令延迟仅34 ms,视频传输速度达到18 Mb/s,平均点播时间为1 320 ms,且拒绝用户数少。 展开更多
关键词 DVB IP传输 视频点播 复合流 WEB页面 PBHS算法 播出控制
在线阅读 下载PDF
基于改进遗传算法的临时转播塔结构优化设计方法
13
作者 邢国华 陆勇健 +1 位作者 苗鹏勇 陈思锦 《浙江大学学报(工学版)》 北大核心 2025年第3期469-479,共11页
针对临时转播塔结构用钢质量较大且设计过程精细化程度低的问题,提出模块化临时转播塔结构及其优化设计方法.所提设计方法将参数化建模与综合优化相结合,利用ANSYS建立结构参数化有限元模型,考虑结构设计参数在寻优过程中引起的风荷载变... 针对临时转播塔结构用钢质量较大且设计过程精细化程度低的问题,提出模块化临时转播塔结构及其优化设计方法.所提设计方法将参数化建模与综合优化相结合,利用ANSYS建立结构参数化有限元模型,考虑结构设计参数在寻优过程中引起的风荷载变化;采用初始替换、差异化、自适应遗传等5种策略提升浮点数编码遗传算法(FGA)的搜索能力和收敛性能,提出改进浮点数编码遗传算法(IFGA),综合优化临时转播塔结构的尺寸、形状和杆件布置形式,实现结构轻量化设计.工程实例的应用表明,模块化临时转播塔结构的力学性能良好;在结构轻量化方面,IFGA算法相较于FGA算法优化结果在用钢质量上降低18.9%,相较于学校算法、鲸鱼算法及改进灰狼算法具有更高的计算效率和寻优能力;建议的优化设计方法高效、可靠,能在确保结构安全的前提下较初始方案在用钢质量上降低33.2%. 展开更多
关键词 结构优化 遗传算法 有限元 轻量化设计 临时转播塔
在线阅读 下载PDF
广播式社交网络平台用户的信息规避行为动机研究
14
作者 黄微 周思蒙 刘逸伦 《现代情报》 北大核心 2025年第3期25-39,共15页
[目的/意义]本文通过探究广播式社交网络平台用户信息规避行为的外部诱因和内在动机,揭示用户信息规避行为规律,为用户提高信息利用效率、企业提高信息服务质量提出指导性建议。[方法/过程]基于S-O-R模型,通过质性研究方法分析广播式社... [目的/意义]本文通过探究广播式社交网络平台用户信息规避行为的外部诱因和内在动机,揭示用户信息规避行为规律,为用户提高信息利用效率、企业提高信息服务质量提出指导性建议。[方法/过程]基于S-O-R模型,通过质性研究方法分析广播式社交网络平台用户信息规避行为要素及作用机制,并基于其行为内在动机及作用路径构建广播式社交网络平台用户信息规避行为模型。[结果/结论]信息过载、信息兴趣、弱连接性作为外部刺激,引发用户感知成本动机、感知收益动机,进而驱动用户信息规避行为。 展开更多
关键词 信息规避 广播式社交网络平台 S-O-R模型 扎根理论 行为动机
在线阅读 下载PDF
云计算环境下多模态异构网络数据安全存储方法
15
作者 李晓静 杨秀杰 《现代电子技术》 北大核心 2025年第6期63-67,共5页
为了快速、准确地存储多模态异构网络数据,提出一种云计算环境下多模态异构网络数据安全存储方法。采用编译套件部署多模态异构网络,利用后端编译模组生成网络的初始化配置,再利用前端编译模组分析与优化网络。针对多模态异构网络,构建... 为了快速、准确地存储多模态异构网络数据,提出一种云计算环境下多模态异构网络数据安全存储方法。采用编译套件部署多模态异构网络,利用后端编译模组生成网络的初始化配置,再利用前端编译模组分析与优化网络。针对多模态异构网络,构建包括客户端、服务器端、云存储服务插件、元数据存储的私有云存储架构。私有云存储架构采用虚拟化加解密方式,运行基于匿名广播加密的数据加密算法,引入拉格朗日插值方法,利用数据对应的会话密钥实现多模态异构网络数据的安全存储。实验结果表明,所提方法能够高效地存储多模态异构网络数据,数据传输的吞吐量高于3 Mb/s,加解密耗时低,存储的完整性高。 展开更多
关键词 云计算环境 多模态 异构网络 数据安全 存储方法 匿名广播加密 云存储架构
在线阅读 下载PDF
Programming Technology of IP Multicast and Broadcast Based on Socket 被引量:2
16
作者 李冬霞 苏广川 沈瑛 《Journal of Beijing Institute of Technology》 EI CAS 2001年第3期316-321,共6页
Beginning with the simple introduction of socket which is the most commonly used application program interfaces in UNIX/LINUX communication domain, the concrete programming procedures to realize multicast and broadcas... Beginning with the simple introduction of socket which is the most commonly used application program interfaces in UNIX/LINUX communication domain, the concrete programming procedures to realize multicast and broadcast based on socket is provided, according to TCP/IP protocol in LINUX system. The acquiring and converting of broadcast destination address and multicast address, the setting of multicast options, the joining in and withdrawing from the multicast group, and the receiving and sending of datagram are all demonstrated in it, the related system calls and simple explication of C programming are also included. 展开更多
关键词 SOCKET MULTICAST broadcast LINUX
在线阅读 下载PDF
基于区块链的车联网跨域数据安全传输系统设计 被引量:1
17
作者 陈晨 王斓凯 施佺 《现代电子技术》 北大核心 2025年第1期71-79,共9页
为有效应对车联网系统在数据传输过程中的安全问题,提出一种基于区块链的车联网跨域数据安全传输系统。该系统将车联网安全数据传输过程划分为注册、安全通信与数据共享三个关键环节。在注册阶段,车辆和路边单元需要通过可信机构完成注... 为有效应对车联网系统在数据传输过程中的安全问题,提出一种基于区块链的车联网跨域数据安全传输系统。该系统将车联网安全数据传输过程划分为注册、安全通信与数据共享三个关键环节。在注册阶段,车辆和路边单元需要通过可信机构完成注册,以确保其的身份合法性;在通信阶段,为了减少路边单元与车辆频繁认证,设计了跨域认证的方法,保障数据传输的可靠性和完整性,并引入假名来保护用户隐私;在共享阶段,文中设计了基于多线程遍历共享广播森林的事务广播算法,利用广度优先搜索思想建立广播森林,并使用多线程遍历进行数据事务广播传输。实验仿真结果显示,文中方案的签名计算成本减少70%,验证计算成本减少41%;其次,在ER模型下,相比使用Gossip协议进行事务数据传输,该方案中交通数据事务总时间降低了93%;在BA模型下降低了87%。 展开更多
关键词 区块链 车联网 身份认证 密钥协商 广播森林 数据安全传输系统
在线阅读 下载PDF
广播标记(Broadcast Flag)技术 被引量:3
18
作者 王磊 谢锦辉 《广播与电视技术》 北大核心 2006年第4期48-50,共3页
近来,业界都在讨论广播标记(BroadcastFlag)技术。本文详细介绍了广播标记技术产生的背景、原理与实现,以及争论的焦点问题;最后针对广播标记技术是否可以应用于我国的数字电视领域给出了我们的看法和建议。
关键词 广播标记 broadcast FLAG 再分发控制描述子 ATSC
在线阅读 下载PDF
天拓五号卫星天基物联网系统关键技术与在轨验证
19
作者 李松亭 陈利虎 +3 位作者 余孙全 崔俊伟 赵勇 杨磊 《国防科技大学学报》 北大核心 2025年第1期168-180,共13页
天基物联网是地基物联网的有效补充和延拓,是建设万物互联、泛在感知的基础性技术手段。以天拓五号卫星中集成的天基物联网系统为例,瞄准覆盖陆海空的多域多场景应用需求,重点解决船舶自动识别系统信号、广播式自动相关监视系统信号的... 天基物联网是地基物联网的有效补充和延拓,是建设万物互联、泛在感知的基础性技术手段。以天拓五号卫星中集成的天基物联网系统为例,瞄准覆盖陆海空的多域多场景应用需求,重点解决船舶自动识别系统信号、广播式自动相关监视系统信号的高可靠侦收以及数据搜集系统的多址接入问题,实现航海目标、航空目标的实时监管以及极海量窄带物联传感终端的全球布局,为我国天基物联网的论证、建设、发展以及规模应用提供借鉴方案。 展开更多
关键词 天拓五号 天基物联网 船舶自动识别系统 广播式自动相关监视系统 数据搜集系统自然能
在线阅读 下载PDF
多通道传输技术在应急广播系统中的应用 被引量:1
20
作者 周振庆 边巴加布 谢琳 《电视技术》 2025年第1期138-140,共3页
突发性事件的频繁发生对信息传递系统提出了更高的要求,应急广播系统作为重要的应急信息传播手段,必须具备高效、可靠的传输能力。探讨多通道传输技术在应急广播系统中的应用,详细分析数字广播、卫星通信、无线网络等不同技术的原理及... 突发性事件的频繁发生对信息传递系统提出了更高的要求,应急广播系统作为重要的应急信息传播手段,必须具备高效、可靠的传输能力。探讨多通道传输技术在应急广播系统中的应用,详细分析数字广播、卫星通信、无线网络等不同技术的原理及其在不同场景中的应用。通过对这些技术的性能进行比较,讨论其优点与不足,并对其适用环境和未来发展方向做出预测。基于现有技术的发展趋势,未来应急广播系统在提升传输速度、覆盖范围和抗干扰能力方面具有广阔的发展前景。 展开更多
关键词 应急广播系统 多通道 传输技术
在线阅读 下载PDF
上一页 1 2 235 下一页 到第
使用帮助 返回顶部