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CSMA(载波监听多路访问)控制策略中有3种坚持退避算法，其中一种是：“一旦介质空闲就发送数据，假如介质是忙的，继续监听，直到介质空闲后立即发送数据；如果有冲突就退避，然后再监听”这种退避算法称为 (1) 算法。这种算法的主要特点是 (2) 。CSMA/CD在CSMA的基础上增加了冲突检测功能。网络中的某个发送站点一旦检测到冲突，它就立即停止发送，并发冲突码，其他站点都会 (3) 。如果站点发送时间为1，任意两个站之间的传播延迟为t，若能正常检测到冲突，对于基带总线网络，t的值应为 (4) ；对于宽带总线网络，t的值应为 (5) 。 3（）
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[A] Why is foreign text "rendered meaningless" when passed through an on-line translation tool According to Sabine Reul, who runs a Frankfurt-based translation company, translation tools have limited uses, and problems arise when web users expect too much from them. "A translation tool works for some things," says Reul, "Say a British company wants to order a box of screws from a German supplier. A sentence like ’We need one box of a certain type of screw’ is something that a machine could translate reasonably accurately--though primitively."[B] Yet when it comes to translating blocks of text—words and sentences that convey thoughts and sentiments, on-line tools are bound to fail, she adds. "Beyond simple sentences, the on-line process simply doesn’t work because machines don’t understand grammar and semantics, never mind idiom and style." "Language is not a system of signs in the mechanical sense of the word", says Reul, "It is a living medium that is used to convey thought. And that is where machines fail. Human input is indispensable as long as computers cannot think." Reul and other translators look forward to the day when clever computers might help to ease their workload--but that time has not arrived yet.[C] Earlier this month the small German town of Homberg-an-der-Efze, north of Frankfurt, had to pulp an entire print run of its English language tourism brochure after officials used an Internet translating tool to translate the German text. According to one report, the brochure was "rendered meaningless" by the on line tool. Martin Wagner, mayor of Homherg-an-der-Efze, admits that the town made a "blunder". As a result of officials trying to save money by getting the Internet to do a translator’s job, a total of 7,500 brochures had to be binned.[D] "It would be nice if computers could do the job. And certainly the quest for machine translation has prompted a lot of linguistic research that may prove valuable in unforeseen ways. But experience to date confirms that even the most subtle computer program doesn’t think and you need to be able to think in order to translate."[E] This story highlights some of the pitfalls of translating on line. There are many instant translation tools on the web, but they are best used for individual words and short phrases, rather than for brochures, books or anything complex. For example, one of the joys of the web is that it grants you access to an array of foreign news sources. Yet if you were to use a translation tool to try to make sense of such reports, you could end up with a rather skewed and surreal view of the world.[F] Until the dawn of thinking computers, on-line translation tools are best reserved for words, basic sentences and useful holiday phrase. For tourism brochures, newspaper reports and the rest, you will have to rely on some old fashioned "human input".[G] Relying on on-line translation tools can be a risky business, especially if you expect too much of it. For the time being, might translation be something best left to the humansOrder: 43
N-ISDN是在 (1) 基础上建立起来的网络，能够提供的最高速率是 (2) 。网络提供基本接口速率时，传输声音需要使用 (3) ，一路话音占用的数据传输率是 (4) ，占用户可用带宽的比例是 (5) 。 1（）
OSI网络管理标准定义了网管的5大功能。比如对每一个被管理对象的每一个属性设置阈值、控制阈值检查和告警的功能属于 (1) ；接收报警信息、启动报警程序、以各种形式发出警报的功能属于 (2) ；接收告警事件、分析相关信息、及时发现正在进行的攻击和可疑迹象的功能属于 (3) ，上述事件捕捉和报告操作可由管理代理通过SNMP和传输网络将 (4) 发送给管理进程，这个操作 (5) 。 3（）
设信道带宽为3000Hz，根据尼奎斯特(Nyquist)定理，理想信道的波特率为 (1) 波特，若采用QPSK调制，其数据速率应为 (2) ，如果该信道信噪比为30dB，则该信道的带宽约为 (3) 。设信道误码率为10-5，帧长为10Kb，差错为单个错，则帧出错的概率为 (4) 。若整个报文被分成5个帧，帧出错的概率为0.1，纠错重发以报文为单位，则整个报文的平均发送次数约为 (5) 次。 1（）
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