以太网桥接专用集成电路的实现

介绍了一种基于高级数据链路控制(HDLC)协议，实现以太网桥接的专用集成电路技术，介绍了该集成电路的系统组成和主要模块功能，着重讨论了高级数据链路控制(HDLC)协议的算法设计以及FIFO控制模块中双指针操作方式的技术实现。     

用FPGA实现可监测冲突的HDLC控制器

HDLC（高级数据链路控制）协议是一种数据链路层协议,促进传送到下一层的数据在传送过程中能够被准确的接受。协议规定所有信息的传送以‘01111110’比特流开始,以‘01111110’结束,信息段如连续出现5个‘1’的话,协议要求插一个‘0’,协议不含特殊的控制代码。HDLC支持点对点和多路广播连接。本文就是描述了一种HDLC控制器的逻辑设计方法,并能在多路广播时监测总线冲突中做出相应处理。     

一种用于数据链自组网的MAC协议

战争形式的转变推动了数据链组网技术的转变,最新一代的数据链开始采用自组网技术,这也代表了数据链未来的发展方向。MAC协议是数据链自组网的关键技术之一,数据链自组网的MAC协议急需提高抗干扰能力和安全性,增强对突发业务的支持,据此,提出了HPRMA协议。在此对协议的跳频处理增益和抗转发式干扰的效能进行了分析,论证了协议的高抗干扰能力和可实现性。通过仿真,验证了该协议对突发业务的支持。     

C—DOCSIS宽带接入技术

产生的背景 1．技术与业务的双重驱动 2．集中型CMTS技术的优缺势分析 优势：DOCSIS协议定义了物理层,数据链路层,运营维护管理和数据安全等规范。     

ZigBee协议的最新发展

ZigBee是一种新兴的无线通信技术,被广泛应用于无线传感器网络。文章以IEEE802．15．4系列标准为依据,以ZigBee协议栈为基础,着力介绍ZigBee协议物理层、数据链路层、网络层以及应用层,为ZigBee的工程应用奠定坚实的基础。     

宽带IP网数据链路协议帧同步性能研究

在阐述数据链路层帧同步原理的基础上，对应用于宽带IP传送网络中的GFP与HDLC两种数据链路层协议的帧同步性能进行定量的比较，分析表明，GFP高的协议实现性能，高传送效率以及高传输速率等优点使之更适合于下一代高速IP传送网络。     

无线异步转移模式（WATM）的协议

介绍了无线异步转移模式（ＷＡＴＭ）的各层协议，包括物理层协议，介质访问控制层协议，数据链路控制层协议以移动ＡＴＭ协议。     

无线ATM通信网的关键技术与研究现状

本文介绍支持多媒体业务的无线ＡＴＭ通信网的关键技术，如协议分层模型与网络结构、物理层技术、多址访问控制协议、数据链路控制协议和网络管理与控制技术等，并结合国内外的研究现状进行了论述。     

帧中继技术综述

帧中继是对宽带和广域网络进行数据访问的重要技术。本文对帧中继的历史、现状以及帧中继的功能进行阐述，并对帧中继数据链路核心协议中各部门进行详细说明。     

综合业务数字网（三）

(2)数据链路层协议(LAPD) ISDN用户-网络接口链路层协议称为LAPD(Link Access Protocol D channel),它是D信道的数据链路层协议。在这个协议中定义了用户一网络接口上的第2层实体经D信道交换信息的规则。 ①要求:根据S和T接口的特点,LAPD协议应满足以下两个要求: (Ⅰ)因在ISDN中有多个终端经同一个接口接入网络,所以该协议必须支持接口上多个终端的工     

基于NIOS技术的2.5Gb/s PoS信号测试平台设计

设计了一台基于NIOS技术的2.5Gb/s PoS信号测试平台,可以从物理层、数据链路层和网络层三个层次对输入PoS信号的相关特性进行测试,并可兼容2.5Gb/s整体PoS、622Mb/s整体PoS和155Mb/s整体Pos三种格式.该系统采用了高速光电转化、大规模可编程逻辑器件、NIOS软核等技术,能够为高速SDH光纤网的运营维护和PoS设备的开发发挥很好的作用.     

基于SDH的MSTP中的数据交换芯片设计

针对在SDH上构建多业务传输平台(MSTP)的需求,介绍了一种能在SDH传输和接入设备中提供灵活的数据业务支持的PoS(PacketoverSDH)数据交换芯片的设计方法。该芯片基于共享存储器的交换结构,采用了先进的流水线设计方式以提高整体交换容量。芯片支持服务质量保证(QoS)和组播(Multicast)功能,可用于SDH传输和接入设备中,为SDH上的数据业务支持提供简单而高效的解决方案。     

执行中文分词和词性标注的统一框架

The paper proposes a unified framework to combine the advantages of the fast one-at-a-time approach and the high-performance all-at-once approach to perform Chinese Word Segmentation (CWS) and Part-of-Speech (PoS) tagging. In this framework, the input of the PoS tagger is a candidate set of several CWS results provided by the CWS model. The widely used one-at-a-time approach and all-at-once approach are two extreme cases of the proposed candidate-based approaches. Experiments on Penn Chinese Treebank 5 and Tsinghua Chinese Treebank show that the generalized candidate-based approach outperforms one-at-a-time approach and even the all-at-once approach. The candidate-based approach is also faster than the time-consuming all-at-once approach. The authors compare three different methods based on sentence, words and character-intervals to generate the candidate set. It turns out that the word-based method has the best performance.     

Weighted voting on the blockchain: Improving consensus in proof of stake protocols

Proof of stake (PoS) protocols rely on voting mechanisms to reach consensus on the current state. If an enhanced majority of staking nodes, also called validators, agree on a proposed block, then this block is appended to the blockchain. Yet these protocols remain vulnerable to faults caused by validators who abstain either accidentally or maliciously. To protect against such faults while retaining the PoS selection and reward allocation schemes, we study weighted voting in validator committees. We formalize the block creation process and introduce validators' voting profiles which we update by a multiplicative weights algorithm relative to validators' voting behavior and aggregate blockchain rewards. Using this framework, we leverage weighted majority voting rules that optimize collective decision making to show, both numerically and analytically, that the consensus mechanism is more robust if validators' votes are appropriately scaled. We raise potential issues and limitations of weighted voting in trustless, decentralized networks and relate our results to the design of current PoS protocols.     

6G oriented blockchain based Internet of things data sharing and storage mechanism

Considering the heterogeneity of various IoT system and the single point failure of centralized data-processing platform,a decentralized IoT data sharing and storage method based on blockchain technology was proposed.The block consensus and decentralized storage of shared data were realized through the PoS consensus mechanism.A block layered propagation mechanism between consensus node and verified node was proposed based on the Gossip protocol.The block propagation delay model and decentralization evaluation model of blockchain networks were derived.The trade-off between the block propagation delay and the decentralization degree of networks was analyzed.The simulation results demonstrate that the block propagation delay and degree of network decentralization decrease with the increase of minimal capabilities of consensus nodes.As an application example,in the trajectory data sharing scenario of confirmed patients,the data sharing smart contract is implemented and tested based on the Ethereum development platform.     

基于SDH/SONET的IP数据传送技术分析

SDH/SONET是目前最主要的传输技术,网络应用则以IP业务为中心,IP在SDH/SONET上的传送是一个重要问题.本文讨论IP在SDH/SONET上传送的传统PoA和PoS技术的基础上,详细分析了两种新的协议--简单数据链路(SDL,Simple Data Link)协议和通用成帧规程(GFP,Generic Framing Procedure),研究了各种协议技术的优缺点.     

面向机器翻译的英语词性标注研究及其应用

A hybrid approach to English Part-of-Speech (PoS) tagging with its target application being English-Chinese machine translation in business domain is presented, demonstrating how a present tagger can be adapted to learn from a small amount of data and handle unknown words for the purpose of machine translation. A small size of 998 k English annotated corpus in business domain is built semi-automatically based on a new tagset; the max-imum entropy model is adopted, and rule-based approach is used in post-processing. The tagger is further applied in Noun Phrase (NP) chunking. Exper-iments show that our tagger achieves an accuracy of 98.14%, which is a quite satisfactory result. In the application to NP chunking, the tagger gives rise to 2.21% increase in F-score, compared with the results using Stanford tagger.     

Performance analysis and comparison of PoW,PoS and DAG based blockchains

In the blockchain, the consensus mechanism plays a key role in maintaining the security and legitimation of contents recorded in the blocks. Various blockchain consensus mechanisms have been proposed. However, there is no technical analysis and comparison as a guideline to determine which type of consensus mechanism should be adopted in a specific scenario/application. To this end, this work investigates three mainstream consensus mechanisms in the blockchain, namely, Proof of Work (PoW), Proof of Stake (PoS), and Direct Acyclic Graph (DAG), and identifies their performances in terms of the average time to generate a new block, the confirmation delay, the Transaction Per Second (TPS) and the confirmation failure probability. The results show that the consensus process is affected by both network resource (computation power/coin age, buffer size) and network load conditions. In addition, it shows that PoW and PoS are more sensitive to the change of network resource while DAG is more sensitive to network load conditions.     

SDH以太共享环在城域网的应用

随着因特网和数据业务的爆炸性增长，城域网的主要业务正在从话音向数据转移。然而过去的城域传送网是为话音业务设计的，所以采用的是TDMM网络(SDH、SONET)。本首先介绍了基于SDH网络传送数据业务的几种新技术，如：POS、GFP、LCAS、RPR、共享以太环等，以及可以实现业务隔离、保证安全的VLAN、VLAN嵌套技术，然后对各种城域网数据传输技术进行了比较，最后分新了薪一代的MSTP设各府该具有的几个特点。     

无线传感器网络视频传输技术研究

对无线传感器网络中的视频传输问题进行了研究。无线传感器网络中传输视频数据的难点,在于如何在节点资源有限的网络中确保视频业务的质量。分析并比较了基于单层协议的视频传输技术和基于多层设计的视频传输技术2类视频传输技术,得出结论：2者各有优缺点,单层协议设计与优化简单、扩展性强,但整体性能不一定最佳;跨层优化设计难度较大,但设计得当,性能优于单层协议。