计算机网络中英翻译
ACK (ACKnowledgement) 确认帧
ADSL (Asymmetric Digital Subscriber Line) 非对称数字用户线
AN (Access Network ）接入网
ANSI (American National Standards Institute) 美国国家标准协会
AP (Access Point) 接入点
API (Application Programming Interface) 应用编程接口
APNIC (Asia Pacific Network Information Center) 亚太网络信息中心
ARP （ Address Resolution Protocol ）地址解析协议
ARPA (Advanced Research Project Agency)美国国防部远景研究规划局（高级研究计划署）ARQ (Automatic Repeat reQuest) 自动请求重发
ATM (Asynchronous Transfer Mode) 异步传递方式
ATU (Access Termination Unit) 接入端接单元
ATU-C (Access Termination Unit Central Office ）端局接入端接单元
ATU-R (Access Termination Unit Remote) 远端接入端接单元
AUI (Attachment Unit Interface ）连接接口单元
AWT （ Abstract Window Toolkit ）抽象窗口工具箱
BECN (Backward Explicit Congestion Notification) 反向显式拥塞通知
BER (Basic Encoding Rule) 基本编码规则
BGP (Border Gateway Protocol) 边界网关协议
BSA (Basic Service Area) 基本服务区
BSS (Basic Service Set) 基本服务集
BNA 宝来网络体系结构
CAC (Connection Admission Control) 连接准许控制
CAP (Carrierless Amplitude Phase) 无载波振幅相位调制
CATV (Community Antenna TV, CAble TV) 有线电视
CBR （ Constant Bit Rate ）恒定比特率
CCIR (Consultative Committee，International Radio) 国际无线电咨询委员会
CCITT (Consultative Committee, International Telegraph and Telephone)国际电报电话咨询委员会
CCP 通信控制处理机
CDM (Code Division Multiplexing) 码分复用
CDMA (Code Division Multiplex Access) 码分多址
CNNIC (Network Information Center of China) 中国互联网络信息中心
CRC (Cyclic Redundancy Check) 循环冗余检验
CSMA/CD (Carrier Sense Multiple Access ／ Collision Detection)载波监听多点接入/碰撞检测
CSU/DSU （ Channel Service Unit/Data Service Unit) 信道服务单元／数据服务单元
CTD (Cell Transfer Delay) 信元传送时延
DACS (Digital Access and Cross-connect System) 数字交接系统
DCA 数据通信体系结构
DCE (Data Circuit-terminating Equipment) 数据电路端接设备
DE (Discard Eligibility) 丢弃指示
DES (Data Encryption Standard) 数据加密标准
DHCP (Dynamic Host Configuration Protocol) 动态主机配置协议
DLCI (Data Link Connection Identifier) 数据链路连接标识符
DMT (Discrete Multi-Tone) 离散多音（调制）
DNS (Domain Name System) 域名系统
DNA 数据网络系统结构
DSL (Digital Subscriber Line) 数字用户线
DSLAM (DSL Access Multiplexer) 数字用户线接入复用器
DSSS (Direct Sequence Spread Spectrum) 直接序列扩频
DTE (Data Terminal Equipment) 数据终端设备
DVMRP (Distance Vector Multicast Routing Protocol) 距离向量多播路由选择协议DWDM (Dense WDM) 密集波分复用
EGP (External Gateway Protocol) 外部网关协议
EIA (Electronic Industries Association ）美国电子工业协会
ESP (Encapsulating Security Payload) 封装安全有效载荷
ESS 伍 xtended Service Set) 扩展的服务集
FCS (Frame Check Sequence) 帧检验序列
FDDI (Fiber Distributed Data Interface ）光纤分布式数据接口
FDM (Frequency Division Multiplexing) 频分复用
FEC (Forwarding Equivalence Class) 转发等价类
FEC (Forward Error Correction) 前向纠错
FHSS (Frequency Hopping Spread Spectrum) 跳频扩频
FIFO （ First In First Out) 先进先出
FQ (Fair Queuing) 公平排队
FR (Frame Relay) 帧中继
FSK (Frequency Shift Keying) 移频键控
FTP (File Transfer Protocol ）文件传送协议
FTTB (Fiber To The Building) 光纤到大楼
FTTC (Fiber To The Curb ）光纤到路边
FTTH (Fiber To The Home) 光纤到家
FTTD (Fiber To The Desk) 光纤到桌面
FTTZ(Fiber To The Zone ）光纤到小区
FTTO (Fiber To The Office) 光纤到办公室
FTTF (Fiber To The Floor) 光纤到楼层
GIF (Graphics Interchange Format) 图形交换格式
GII (Global Information Infrastructure) 全球信息基础结构，全球信息基础设施GFC （ Generic Flow Control) 通用流量控制
GSM (Group Special Mobile) 群组专用移动通信体制
HDLC (High-level Data Link Control) 面向比特的链路控制规程
HDSL (High speed DSL) 高速数字用户线
HEC (Header Error Control) 首部差错控制
HFC (Hybrid Fiber Coax) 光纤同轴混合（网）
HTML (HyperText Markup Language) 超文本置标语言
HTTP (HyperText Transfer Protocol) 超文本传送协议
IAB (Internet Architecture Board) 因特网体系结构委员会
IAC （ Interpret As Command ）作为命令解释
IAHC (Internet International Ad Hoc Committee ）因特网国际特别委员会
ICMP （ Internet Control Message Protocol ）因特网控制报文协议
IDEA (International Data Encryption Algorithm) 国际数据加密算法
IEEE电气和电子工程师协会
IESG (Internet Engineering Steering Group) 因特网工程指导小组
IETF (Internet Engineering Task Force) 因特网工程部
IFS (Inter Frame Space) 帧间间隔
IGMP (Internet Group Management Protocol) 因特网组管理协议
IGP (Interior Gateway Protocol) 内部网关协议
IM (Instant Messaging) 即时传信
IMAP (Internet Message Access Protocol) 因特网报文存取协议
IMP （ Interface Message Processor) 接口报文处理机
IP (Internet Protocol ）网际协议
IR (InfraRed ）红外技术
IRTF （ Internet Research Task Force ）因特网研究部
ISDN (Integrated Services Digital Network) 综合业务数字网
ISO （ International Organization for Standardization ）国际标准化组织
ISOC (Internet Society) 因特网协会
ISP （ Internet Service Provider) 因特网服务提供者
ITU （ International Telecommunication Union ）国际电信联盟
ITU-T （ ITU Telecommunication Standardization Sector) 国际电信联盟电信标准化部门JPEG (Joint Photographic Expert Group) 联合图像专家组标准
KDC (Key Distribution Center) 密钥分配中心
LAN (Local Area Network ）局域网
LANE (LAN Emulation ）局域网仿真
LAPB (Link Access Procedure Balanced) 链路接入规程（平衡型）
LCP (Link Control Protocol) 链路控制协议
LDP (Label Distribution Protocol) 标记分配协议
LLC (Logical Link Control) 逻辑链路控制
LSP (Label Switched Path) 标记交换路径
LSR (Label Switching Router) 标记交换路由器
MAC (Medium Access Control) 媒体接入控制
MAN (Metropolitan Area Network) 城域网
MAU (Medium Attachment Unit) 媒体连接单元
MBONE (Multicast Backbone On the InterNEt ）多播主干网
MBS (Maximum Burst Size ）最大突发长度
MCR (Minimum Cell Rate ）最小信元速率 MCU (Multipoint Control Unit)多点控制单元
MD (Message Digest) 报文摘要
MDI (Medium Dependent Interface ）媒体相关接口
MIB (Management Information Base) 管理信息库
MIME (Multipurpose Internet Mail Extensions) 通用因特网邮件扩充
modem 调制解调器
MOTIF (Message Oriented Text Interchange System) 面向报文的电文交换系统
MPEG (Motion Picture Experts Group) 活动图像专家组标准
MPOA (MultiProtocol Over ATM) 多协议在 ATM 上运行
MPLS (MultiProtocol Label Switching) 多协议标记交换
MRU (Maximum Receive Unit) 最大接收单元
MSS (Maximum Segment Size) 最长报文段
MTU (Maximum Transfer Unit) 最大传送单元
NAK (Negative AcKnowlegement) 否认帧
NAP （ Network Access Point) 网络接入点
N.ISDN (Narrowband-ISDN) 窄带综合业务数字网
NAT (Network Address Translation ）网络地址转换
NAV (Network Al location Vector) 网络分配向量
NCP (Network Control Protocol) 网络控制协议
NFS (Network File System) 网络文件系统
NGI 下一代因特网计划
NIA 网络适配器
NIC (Network Interface Card) 网络接口卡、网卡
NII (National Information Infrastructure) 国家信息基础结构，国家信息基础设施NLRI (Network Layer Reachability Information) 网络层可达性信息
NNI (Network-Node Interface) 网络结点接口
NSF (National Science Foundation) （美国）国家科学基金会
NVT (Network Virtual Terminal ）网络虚拟终端
ODBC （Open Database Connection）开放数据库互连
OSF （Open Software Fundation ）开放软件基金会
OSI （Open System Interconnection ）开放系统互联
PBX （Private Branch eXchange ）用户交换机
PCM (Pulse Code Modulation ) 脉冲编码调制
PCN (Personal Communications Network ) 个人通信网络
PCR （Peak Cell Rate ）峰值信元速率
PCS 个人通信服务 Personal Communications Service
PDH 准同步数字系列
PDA 个人数字助理 Personal Digital Assistant
PDN 公用数据网 Public Data Network
PDU 协议数据单元 Protocol Data Unit
PER 分组差错率 packet error rate
PIR 分组插入率 packet insertion rate
PLCP 物理层会聚协议 Physical Layer Convergence Protocol
PLR 分组丢失率 packet loss rate
PMD 物理媒体相关（子层） Physical Medium Dependent
PPP 点到点协议 Point to Point Protocol
PPTP 点对点隧道协议
PRM 协议参考模型 Protocol Reference Model
PRN 分组无线网 Packet Radio Network
PSN 分组交换节点 Packet Switch Node
PSTN 公用电话交换网 Public Switched Telephone Network
RARP 逆向地址解析协议 Reverse Address Resolution Protocol
RAS 远程访问服务器
RFC 请求评注 Request for Comments
RMON 远程网络管理
Router 路由器
RPC 远程过程调用 Remote Procedure Call
RSVP 资源重复利用协议
RTP 接收和发送端口
RTS 往返样本 Round Trip Sample
RTS 剩余时间标签
SAP 业务接入点 Service Access Point
SAP 服务公告协议 Service Advertising Protocol
SAR 分段和重组(子层) Segmentation and Reassembly
SDH 同步数字系列 Synchronous Digital Hierarchy
SDLC 同步数据链路控制(协议) Advanced Data Communication Control Procedure
SDTV 标准数字电视
SDU 业务数据单元 Service Data Unit
SIPP 增强的简单因特网协议 Simple Internet Protocol Plus
SLIP 串行线路IP Serial Line Interface Protocol
SMDS 交换式多兆比特数据业务 Switched Multimegabit Data Services SMF 单模光纤 Single-mode Fiber
SMT 站点管理 Station Management
SMTP 简单邮件传输协议 Simple Mail Transfer Protocol
SNA 系统网络体系结构 System Network Architecture
SNMP 简单网络管理协议 Simple Network Management Protocol
SNR 信噪比 Signal-Noise ratio
SONET 同步光纤网络 Synchronous Optical Network
STM 同步传输方式 Synchronous Transfer Mode
STP 屏蔽双绞线 Shielded Twisted Pair
STS 同步传输信号 Synchronous Transport Signal
SVC 交换虚电路 Switched Virtual Circuit
Switch 交换机
TCP 传输控制协议 Transmission Control Protocol
TDM 时分多路复用 Time Division Multiplexing
TFTP 单纯文件传输协议 Trivial File Transfer protocol
Telnet 远程登录协议
TIP 终端接口处理机 Terminal Interface Processor
TP 双绞线 Twisted Pair
TSAP 传输层服务访问点 Transport Service Access Point
UDP 用户数据报协议 User Datagram Protocol
USB 通用串行总线 Universal Serial Bus
UTP 非屏蔽双绞线 Unshielded Twisted Pair
VAN 增值网 Value Added Network
VBR 可变比特率 Variable Bit Rate
VCC 虚信道连接 Virtual Channel Connection
VLAN 虚拟局域网 Virtual LAN
VLSI 超大规模集成电路
VOD 点播图像 Video on Demand
VPC 虚路径连接 Virtual Path Connection
VPI 虚路径标识 virtual path identifier
VPN 虚拟专用网络 Virtual Private Network
VRML 虚拟现实造型语言 Virtual Reality Modeling Language
VTP 虚拟隧道协议
WAN 广域网 Wide Area Network
WDM 波分多路复用 Wavelength Division Multiplexing
WWW 万维网 World Wide Web
附录1英文及其译文 Computer Networks Network Goals Some reasons are causing centralized computer systems to give way to networks. The first one is that many organizations already have a substantial number of computers in operation, often located far apart .Initially, each of these computers may have worked in isolation from the other ones, but at a certain time, and management may have decided to connect them to be able to correlate information about the entire organization. Generally speaking, the goal is to make all programs, data, and other resources available to anyone on the network without regard to the physical location of the resource and the user. The second one is to provider high reliability by having alternative sources of supply. With a network, the temporary loss of a single computer is much less serious, because its users can often be accommodated elsewhere until the service is restored. Another important reason for distributing computing power has to do with the relative price of computing versus communication. Now the cost of a small computer is negligible, so it becomes attractive to analyze the data at where it is captured, and only to send occasional summaries back to the computer center, to reduce the communication cost, which now represents a larger percentage of the total cost than it used to. Yet another reason of setting up a computer network is that a computer network can provider a powerful communication medium among widely separated people. Application of Networks One of the main areas of potential network use is access to remote data bases. It may someday be easy for people sitting at their terminals
中英文对照外文翻译 汽车变速器设计 我们知道，汽车发动机在一定的转速下能够达到最好的状态，此时发出的功率比较大，燃油经济性也比较好。因此，我们希望发动机总是在最好的状态下工作。但是，汽车在使用的时候需要有不同的速度，这样就产生了矛盾。这个矛盾要通过变速器来解决。 汽车变速器的作用用一句话概括，就叫做变速变扭，即增速减扭或减速增扭。为什么减速可以增扭，而增速又要减扭呢？设发动机输出的功率不变，功率可以表示为 N = w T，其中w是转动的角速度，T 是扭距。当N固定的时候，w与T是成反比的。所以增速必减扭，减速必增扭。汽车变速器齿轮传动就根据变速变扭的原理，分成各个档位对应不同的传动比，以适应不同的运行状况。 一般的手动变速器内设置输入轴、中间轴和输出轴，又称三轴式，另外还有倒档轴。三轴式是变速器的主体结构，输入轴的转速也就是发动机的转速，输出轴转速则是中间轴与输出轴之间不同齿轮啮合所产生的转速。不同的齿轮啮合就有不同的传动比，也就有了不同的转速。例如郑州日产ZN6481W2G型SUV车手动变速器，它的传动比分别是：1档3.704:１；2档2.202:1；3档1.414:1；4档1:1；5档（超速档）0.802:1。 当汽车启动司机选择1档时，拨叉将1/2档同步器向后接合1档
齿轮并将它锁定输出轴上，动力经输入轴、中间轴和输出轴上的1档齿轮，1档齿轮带动输出轴，输出轴将动力传递到传动轴上（红色箭头）。典型1档变速齿轮传动比是3:1,也就是说输入轴转3圈，输出轴转1圈。 当汽车增速司机选择2档时，拨叉将1/2档同步器与1档分离后接合2档齿轮并锁定输出轴上，动力传递路线相似，所不同的是输出轴上的1档齿轮换成2档齿轮带动输出轴。典型2档变速齿轮传动比是2.2:1，输入轴转2.2圈，输出轴转1圈，比1档转速增加，扭矩降低。 当汽车加油增速司机选择3档时，拨叉使1/2档同步器回到空档位置，又使3/4档同步器移动直至将3档齿轮锁定在输出轴上，使动力可以从轴入轴—中间轴—输出轴上的3档变速齿轮，通过3档变速齿轮带动输出轴。典型3档传动比是1.7:1，输入轴转1.7圈，输出轴转1圈，是进一步的增速。 当汽车加油增速司机选择4档时，拨叉将3/4档同步器脱离3档齿轮直接与输入轴主动齿轮接合，动力直接从输入轴传递到输出轴，此时传动比1:1，即输出轴与输入轴转速一样。由于动力不经中间轴，又称直接档，该档传动比的传动效率最高。汽车多数运行时间都用直接档以达到最好的燃油经济性。 换档时要先进入空档，变速器处于空档时变速齿轮没有锁定在输出轴上，它们不能带动输出轴转动，没有动力输出。 一般汽车手动变速器传动比主要分上述1－4档，通常设计者首先确定最低（1档）与最高（4档）传动比后，中间各档传动比一
计算机网络新技术外文翻译文献 (文档含中英文对照即英文原文和中文翻译) 译文: 计算机网络新技术 摘要 21世纪是一个信息时代的经济，计算机网络技术是这个时期的代表技术，以非常快的、具创造性得不断地发展，并将深入到人民群众的工作，生活和学习中。因此，控制这种技术看起来似乎具有很重要的意义。现在，我主要是采用新技术的几种网络技术在现实生活的应用。 关键字 因特网数字证书数字银包网格存储 3G
1.前言 互联网满36岁，仍然是一个进展中的工作。36年后在加州大学洛杉矶分校的计算机科学家使用15英尺的灰色电缆连接两台笨重的电脑，测试了一种在网络上新的数据交换的方式，这将最终成为互联网依然是一个在取得进展的工作。 大学的研究人员正在试验如何提高网络容量和速度。编程人员正在设法为网页注入更多的智能。并正在进行重新设计网络以减少垃圾邮件（垃圾邮件）和安全麻烦的工作。 与此同时威胁织机：批评人士警告说，商业，法律和政治压力可能会阻碍一些使互联网发展到今天的创新的类型。 斯蒂芬克罗克和温顿瑟夫属于1969年9月2日研究生加入的加州大学洛杉矶分校斯莱昂兰罗克教授工程实验室的团体，作为位无意义的测试数据两台计算机之间默默流动。到第二年的1月，其他三个“节点”加入到了这个网络。 然后是电子邮箱，几年之后，在七十年代后期一个所谓的核心通信协议即TCP / IP 协议，在80年代域名系统和在1990年万维网-现在的第二个最流行的应用背后电子邮件出现了。互联网的扩大，超出其最初的军事和教育领域延伸到了企业和全球的家庭中。 今天，克罗克仍然为互联网工作，为协作设计更好的工具。作为互联网管理机构的安全委员会主席，他正试图保卫系统的核心处理免受来自外部的威胁。 他认识到，他帮助建立的互联网工作远未完成，而这些改变是在商店，以满足多媒体日益增长的需求。网络供应商现唯一的“最佳努力”是在提供的数据包上。克罗克说，需要有更好的保障，以防止跳过和过滤现在常见的视频。 瑟夫，现在在MCI公司说，他希望他建立了有内置安全的互联网。微软，雅虎和美国在线公司，和其他的一些，目前正在努力改进网络，使邮件发送者可以验证的方式发送以降低使用虚假地址发送垃圾邮件。 瑟夫说，现在正在制定许多功能，是不可能立即解决计算速度慢和互联网管道窄，或
《计算机网络》中英文对照 Chapter 1 End system P28 端系统 Modem P29 调制解调器（俗称：猫） Base station P29 基站 Communication link P30 通信链路 Physical media P30 物理介质 Coaxial cable P30 同轴电缆 Fiber optics P30 光纤 Radio spectrum P30 射频频谱 Transmission rate P30 传输速率 Packets P30 （数据）包，或分组 Routers P30 路由器 Link-layer switches P30 链路层交换机 Path P30 路径 ISP (Internet Service Provider) P30 网络服务提供商 TCP (Transmission Control Protocol) P31 传输控制协议 IP ( Internet Protocol) P31 网际协议 Intranets P31 内网 API (Application Programming Interface) P32 应用程序编程接口Network edge P35 网络边缘 Access Networks P38 接入网 Ethernet P42 以太网 Network core P48 网络核心 Circuit Switching P50 电路转换 Packet Switching 分组交换 FDM (frequency-division multiplexing) P50 频分多路复用 TDM (time-division multiplexing) P50 时分多路复用 Statistical Multiplexing 统计复用 Store-and-forward 存储转发 Queuing delays P53 排队延迟 Transmission delay P60 传输延迟，或发送延迟 Propagation delay P60 传播延迟 Throughput P59 吞吐量 Internet backbone P57 骨干网 Delay P59 延迟，或时延 Loss P59 丢包 Packet-Switched Network P59 分组交换网络 Nodal processing delay P60 节点处理延迟 End-to-end delay P66 端到端延迟 Instantaneous throughput P68 瞬时吞吐量
附录 附录A. Manual Transmission It’s no secret that cars with manual transmissions are usually more fun to drive than the automatic-equipped counterparts. If you have even a passing interest in the act of driving, then chances are you also appreciate a fine-shifting manual gearbox. But how does a manual transmission actually work? A history hows that manual transmissions preceded automatics by several decades. In fact，up until General Motors offered an automatic in 1938, all cars were of the shift-it-yourself variety. While it’s logical for many types of today’s vehicles to be equipped with an automatic――such as a full-size sedan, SUV or pickup――the fact remains that nothing is more of a thrill to drive than a tautly suspended sport sedan, snort coupe or two-sealer equipped with a precise-shifting five-or six-speed gearbox． We know whicn types or cars have manual trannies. Now let’s take a look at how they work. From the most basic four-speed manual in a car from the’60s to the most high-tech six-speed one in a car of today, the principles of a manual gearbox are the same. The driver must shift from gear to gear. Normally, a manual transmission bolts to a clutch housing (or bell housing）, in turn, bolts to the back of the engine. If the vehicle has front-wheel drive,
The development of automobile As the world energy crisis and the war and the energy consumption of oil -- and are full of energy in one day someday it will disappear without a trace. Oil is not inresources. So in oil consumption must be clean before finding a replacement. With the development of science and technology the progress of the society people invented the electric car. Electric cars will become the most ideal of transportation. In the development of world each aspect is fruitful especially with the automobile electronic technology and computer and rapid development of the information age. The electronic control technology in the car on a wide range of applications the application of the electronic device cars and electronic technology not only to improve and enhance the quality and the traditional automobile electrical performance but also improve the automobile fuel economy performance reliability and emission spurification. Widely used in automobile electronic products not only reduces the cost and reduce the complexity of the maintenance. From the fuel injection engine ignition devices air control and emission control and fault diagnosis to the body auxiliary devices are generally used in electronic control technology auto development mainly electromechanical integration. Widely used in automotive electronic control ignition system mainly electronic control fuel injection system electronic control ignition system electronic control automatic transmission electronic control ABS/ASR control system electronic control suspension system electronic control power steering system vehicle dynamic control system the airbag systems active belt system electronic control system and the automatic air-conditioning and GPS navigation system etc. With the system response the use function of quick car high reliability guarantees of engine power and reduce fuel consumption and emission regulations meet standards. The car is essential to modern traffic tools. And electric cars bring us infinite joy will give us the physical and mental relaxation. Take for example automatic transmission in road can not on the clutch can achieve automatic shift and engine flameout not so effective improve the driving convenience lighten the fatigue strength. Automatic transmission consists mainly of hydraulic torque converter gear transmission pump hydraulic control system electronic control system and oil cooling system etc. The electronic control of suspension is mainly used to cushion the impact of the body and the road to reduce vibration that car getting smooth-going and stability. When the vehicle in the car when the road uneven road can according to automatically adjust the height. When the car ratio of height low set to gas or oil cylinder filling or oil. If is opposite gas or diarrhea. To ensure and improve the level of driving cars driving stability. Variable force power steering system can significantly change the driver for the work efficiency and the state so widely used in electric cars. VDC to vehicle performance has important function it can according to the need of active braking to change the wheels of the car car motions of state and optimum control performance and increased automobile adhesion controlling and stability. Besides these appear beyond 4WS 4WD electric cars can greatly improve the performance of the value and ascending simultaneously. ABS braking distance is reduced and can keep turning skills effectively improve the stability of the directions simultaneously reduce tyre wear. The airbag appear in large programs protected the driver and passengers safety and greatly reduce automobile in collision of drivers and passengers in the buffer to protect the safety of life. Intelligent electronic technology in the bus to promote safe driving and that the other functions. The realization of automatic driving through various sensors. Except some smart cars equipped with multiple outside sensors can fully perception of information and traffic facilities
附录A With the new network technology and application of the continuous rapid development of the computer network should. Use of becoming increasingly widespread, the role played by the increasingly important computer networks and human. More inseparable from the lives of the community's reliance on them will keep growing. In order for computers to communicate, they must speak the same language or protocol. In the early days of networking, networks were disorganized in many ways. Companies developed proprietary network technologies that had great difficulties in exchanging information with other or existing technologies; so network interconnections were very hard to build. To solve this problem, the International Organization for Standardization（ISO）created a network model that helps vendors to create networks compatible with each other. Finding the best software is not easy. A better understanding of what you need and asking the right questions makes it easier. The software should be capable of handling challenges specific to your company. If you operate multiple distribution centers, it may be beneficial to create routes with product originating from more than one depot. Few software providers though, are capable of optimizing routes using multiple depots. The provider should be able to support installation of its product. Make sure to clearly understand what training and software maintenance is offered. Obviously, selecting the right routing/scheduling software is critically important. Unfortunately, some companies are using software that may not be best suited to their operation. Logistics actives with responsibility for approving the software ought to be comfortable they've made the right decision. It is important to realize that not all routing/scheduling software is alike！ There questions to ask are：Which operating system is used？How easy is the software to use？Here is a good way to tell. Ask if its graphical user interface（GUI）is flexible. Find out about installation speed - how long does it take？Is the software able to route third party customers with your core business？When was the software originally released and when was it last upgraded？ In 1984, ISO released the Open Systems Interconnection（OSI）reference model,
AN (Access Network) 接入网 ADSL (Asymmetric Digital Subscriber Line)：非对称数字用户线 ADSL (Asymmetric Digital Subscriber Line)：非对称数字用户线 ATU (Access Termination Unit) 接入端接单元 ARP (Address Resolution Protocol) 地址解析协议 ARQ (Automatic Repeat reQuest) 自动重传请求 BER (Bit Error Rate) 误码率 CBT (Core Based Tree) 基于核心的转发树 CIDR (Classless Inter-Domain Routing) 无分类域间路由选择 DSL (Digital Subscriber Line) 数字用户线 DMT (Discrete Multi-Tone) 离散多音调 DSLAM (DSL Access Multiplexer) 数字用户线接入复用器 DVMRP (Distance Vector Multicast Routing Protocol) 距离向量多播路由选择协议EGP (External Gateway Protocol外部网关协议 FTTH (Fiber To The Home) 光纤到家 FTTB (Fiber To The Building) 光纤到大楼 FTTC (Fiber To The Curb) 光纤到路边 FCS (Frame Check Sequence) 帧检验序列 HDSL (High speed DSL)：高速数字用户线 IGP (Interior Gateway Protocol内部网关协议 ICMP(Internet Control Message Protocol) 网际控制报文协议 ISP (Internet Service Provider) 因特网服务提供者 ICMP(Internet Control Message Protocol) 网际控制报文协议 IGMP (Internet Group Management Protocol) 网际组管理协议 LCP (Link Control Protocol) 链路控制协议 LLC (Logical Link Control) 子层逻辑链路控制 LAN (Local Area Network) 局域网 MAC (Medium Access Control) 媒体接入控制 MOSPF (Multicast Extensions to OSPF) 开放最短通路优先的多播扩展 MAN (Metropolitan Area Network) 城域网 NCP (Network Control Protocol) 网络控制协议 NAT (Network Address Translation) 网络地址转换 NIC (Network Interface Card) 网络接口卡 OSPF (Open Shortest Path First) 光内部网关协议 ODN (Optical Distribution Node) 分配结点 PAN (Personal Area Network) 个人区域网 PPP (Point-to-Point Protocol) 点对点协议对等方式（P2P 方式） PIM-SM (Protocol Independent Multicast-Sparse Mode) 协议无关多播-稀疏方式PIM-DM (Protocol Independent Multicast-Dense Mode) 协议无关多播-密集方式RTO (RetransmissionTime-Out) 超时重传时间 RPB (Reverse Path Broadcasting) 反向路径广播
外文翻译 文章出处《Tribology International》, 2009, 42(5):714-723 译文： 有限元热分析的陶瓷离合器 1 引言 磨料空转车辆离合器是力封闭联轴器。扭矩和高速传输被压紧表面之间产生的摩擦力所保证。应用陶瓷是因为它作为摩擦介质具有好耐热和耐磨损性能，提供了机会以驱动更高的压力，以及一个低的密度。因此，一个提功率密度启用了一个平行的最小化建筑空间。 测量使用陶瓷饰面离合器盘的第一个原型在卡尔斯鲁厄大学的一个实验室专门从事客车驱动系统进行了测试执行。在分析过程中的有限元（FE）模型是将与测量数据和测量条件的知识所构成。计算的目的是要确定在离合器盘上温度的分布以及环境中的在每一时刻的及时测量目。至关重要的是熟悉的温度范围，为了检验该系统的耐磨特性。因此，重要信息从测量数据中得出。在临界负载的情况下，预计最高温度必须在时间和空间上进行预测，为保护接近发热体的位置测量工具的。 本研究的目的是分析和修改该离合器系统通过改进，以提供更好的工作条件热传导和系统或增加转化成摩擦热的能量的对流。此外，人们希望找到更有效的更好的离合器系统设计方案。 计算是由宇宙星空的设计的软件进行的。在模型开发阶段，非常谨慎，必须采取几何元素，选择适当的简化尺寸，并且由于正确调整的时间步长大量的硬件要求瞬态计算。热物性参数的改变，如表面热对流化系数和热负荷，必须考虑到到在一个持续的基础上在时间和地点方面。离合器系统的分析测试这两方面，只能通过加热隔板连接的两个独立的模型来管理，根据该假说认为，接触温度必须是在两个相同的双方，同时他们要有适当接触，其价值需通过迭代来进行调整。计算显示，该热分区按周期变化，它沿不同的内，外接触环。在不同的冷却特性下，在陶瓷和钢之间的结果是不同的，热流从陶瓷侧面向钢侧流动。此热流也通过迭代确定;它的价值也改变了周期和不同沿着所述内和外接触环。 2 采用工程陶瓷作为摩擦材料的第一个原型机 这款检查过的离合器盘是根据“特定的陶瓷”产品而开发的，此材料的研发过程在流程在卡尔斯鲁厄大学的Institute for Product Development (IPEK)杂志上发表过。此开发过程已经具有的可能性，用于连接到一个真实的传动轴；甚至，它为面板有一个好的初始行为起到一个很好的缓冲作用。磨料配件必须符合以下基本要求：
附录 一、英文原文： The NetWorks Birth of the Net The Internet has had a relatively brief, but explosive history so far. It grew out of an experiment begun in the 1960's by the U.S. Department of Defense. The DoD wanted to create a computer network that would continue to function in the event of a disaster, such as a nuclear war. If part of the network were damaged or destroyed, the rest of the system still had to work. That network was ARPANET, which linked U.S. scientific and academic researchers. It was the forerunner of today's Internet. In 1985, the National Science Foundation (NSF) created NSFNET, a series of networks for research and education communication. Based on ARPANET protocols, the NSFNET created a national backbone service, provided free to any U.S. research and educational institution. At the same time, regional networks were created to link individual institutions with the national backbone service. NSFNET grew rapidly as people discovered its potential, and as new software applications were created to make access easier. Corporations such as Sprint and MCI began to build their own networks, which they linked to NSFNET. As commercial firms and other regional network providers have taken over the operation of the major Internet arteries, NSF has withdrawn from the backbone business. NSF also coordinated a service called InterNIC, which registered all addresses on the Internet so that data could be routed to the right system. This service has now been taken over by Network Solutions, Inc., in cooperation with NSF. How the Web Works The World Wide Web, the graphical portion of the Internet, is the most popular part of the Internet by far. Once you spend time on the Web,you will begin to feel like there is no limit to what you can discover. The Web allows rich and diverse communication by displaying text, graphics, animation, photos, sound and video. So just what is this miraculous creation? The Web physically consists of your personal computer, web browser software, a connection to an Internet service provider, computers called servers that host digital data and routers and switches to direct the flow of information. The Web is known as a client-server system. Your computer is the client; the remote computers that store electronic files are the servers. Here's how it works: Let's say you want to pay a visit to the the Louvre museum website. First you enter the address or URL of the website in your web browser (more about this shortly). Then your browser requests the web page from the web server that hosts the Louvre's site. The Louvre's server sends the data over the Internet to your computer. Your web
Chapter1 1-11.What are two reasons for using layered protocols? (请说出使用分层协议的两个理由) 答：通过协议分层可以把设计问题划分成较小的易于处理的片段。分层意味着某一层的协议的改变不会影响高层或低层的协议。 1-13. What is the principal difference between connectionless communication and connection-oriented communication? (在无连接通信和面向连接的通信两者之间，最主要的区别是什么？) 答：主要的区别有两条。 其一：面向连接通信分为三个阶段，第一是建立连接，在此阶段，发出一个建立连接的请求。只有在连接成功建立之后，才能开始数据传输，这是第二阶段。接着，当数据传输完毕，必须释放连接。而无连接通信没有这么多阶段，它直接进行数据传输。 其二：面向连接的通信具有数据的保序性，而无连接的通信不能保证接收数据的顺序与发送数据的顺序一致。 1-20. A system has an n-layer protocol hierarchy. Applications generate messages of length M bytes. At each of the layers, an h-byte header is added. What fraction of the network bandwidth is filled with headers? (一个系统有n层协议的层次结构。应用程序产生的消息的长度为M字节。在每一层上需要加上一个h字节的头。请问，这些头需要占用多少比例的网络带宽) 答：hn/(hn+m)*100% 1-28. An image is 1024 x 768 pixels with 3 bytes/pixel. Assume the image is uncompressed. How long does it take to transmit it over a 56-kbps modem channel? Over a 1-Mbps cable modem? Over a 10-Mbps Ethernet? Over 100-Mbps Ethernet? (一幅图像的分辨率为1024 x 768像素，每个像素用3字节来表示。假设该图像没有被压缩。请问，通过56kbps的调制解调器信道来传输这幅图像需要多长时间？通过1Mbps的电缆调制解调器呢？通过10Mbps的以太网呢？通过100Mbps的以太网呢?) 答：The image is 1024*768*3 bytes or 2359296 bytes.This is 18874368 bit. At 56,000 bits/sec, it takes about 337.042 sec. At 1,000,000 bits/sec, it takes about 18.874 sec. At 10,000,000 bits/sec, it takes about 1.887 sec. At 100,000,000 bits/sec, it takes about 0.189 sec. Chapter2 2-2. A noiseless 4-kHz channel is sampled every 1 msec. What is the maximum data rate? (一条无噪声4kHz信道按照每1ms一次进行采样，请问最大数据传输率是多少？)