全分散控制方式程控交换机的主要优点有哪些？-查字典考试网

全分散控制方式程控交换机的主要优点有哪些？

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正确答案：

全分散控制方式主要优点如下：

（1）当增加容量或增加新性能时可以增加相应的微处理机，而不会影响原有处理机的能力；

（2）能充分利用微电子技术的进步，方便地引入新技术和新业务；

（3）当发生故障时影响面较小，避免了全系统瘫痪。

答案解析：

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1 There's a dimmer switch inside the sun that causes its brightness to rise and fall on timescales of around 100,000 years - exactly the same period as between ice ages on Earth. So says a physicist who has created a computer model of our star's core. 2 Robert Ehrlich of George Mason University in Fairfax, Virginia, modelled the effect of temperature fluctuations in the sun's interior. According to the standard view, the temperature of the sun's core is held constant by the opposing pressures of gravity and nuclear fusion. However, Ehrlich believed that slight variations should be possible. 3 He took as his starting point the work of Attila Grandpierre of the Konkoly Observatory of the Hungarian Academy of Sciences. In 2005, Grandpierre and a collaborator, Gábor ágoston, calculated that magnetic fields in the sun's core could produce small instabilities in the solar plasma. These instabilities would induce localised oscillations in temperature. 4 Ehrlich's model shows that whilst most of these oscillations cancel each other out, some reinforce one another and become long-lived temperature variations. The favoured frequencies allow the sun's core temperature to oscillate around its average temperature of 13.6 million kelvin in cycles lasting either 100,000 or 41,000 years. Ehrlich says that random interactions within the sun's magnetic field could flip the fluctuations from one cycle length to the other. 5 These two timescales are instantly recognisable to anyone familiar with Earth's ice ages: for the past million years, ice ages have occurred roughly every 100,000 years. Before that, they occurred roughly every 41,000 years. 6 Most scientists believe that the ice ages are the result of subtle changes in Earth's orbit, known as the Milankovitch cycles. One such cycle describes the way Earth's orbit gradually changes shape from a circle to a slight ellipse and back again roughly every 100,000 years. The theory says this alters the amount of solar radiation that Earth receives, triggering the ice ages. However, a persistent problem with this theory has been its inability to explain why the ice ages changed frequency a million years ago. 7 "In Milankovitch, there is certainly no good idea why the frequency should change from one to another," says Neil Edwards, a climatologist at the Open University in Milton Keynes, UK. Nor is the transition problem the only one the Milankovitch theory faces. Ehrlich and other critics claim that the temperature variations caused by Milankovitch cycles are simply not big enough to drive ice ages. 8 However, Edwards believes the small changes in solar heating produced by Milankovitch cycles are then amplified by feedback mechanisms on Earth. For example, if sea ice begins to form because of a slight cooling, carbon dioxide that would otherwise have found its way into the atmosphere as part of the carbon cycle is locked into the ice. That weakens the greenhouse effect and Earth grows even colder. 9 According to Edwards, there is no lack of such mechanisms. "If you add their effects together, there is more than enough feedback to make Milankovitch work," he says. "The problem now is identifying which mechanisms are at work." This is why scientists like Edwards are not yet ready to give up on the current theory. "Milankovitch cycles give us ice ages roughly when we observe them to happen. We can calculate where we are in the cycle and compare it with observation," he says. "I can't see any way of testing [Ehrlich's] idea to see where we are in the temperature oscillation." 10 Ehrlich concedes this. "If there is a way to test this theory on the sun, I can't think of one that is practical," he says. That's because variation over 41,000 to 100,000 years is too gradual to be observed. However, there may be a way to test it in other stars: red dwarfs. Their cores are much smaller than that of the sun, and so Ehrlich believes that the oscillation periods could be short enough to be observed. He has yet to calculate the precise period or the extent of variation in brightness to be expected. 11 Nigel Weiss, a solar physicist at the University of Cambridge, is far from convinced. He describes Ehrlich's claims as "utterly implausible". Ehrlich counters that Weiss's opinion is based on the standard solar model, which fails to take into account the magnetic instabilities that cause the temperature fluctuations. Questions 1-4 Complete each of the following statements with One or Two names of the scientists from the box below. Write the appropriate letters A-E in boxes 1-4 on your answer sheet. A. Attila Grandpierre B. Gábor ágoston C. Neil Edwards D. Nigel Weiss E. Robert Ehrlich 1. ...claims there a dimmer switch inside the sun that causes its brightness to rise and fall in periods as long as those between ice ages on Earth. 2. ...calculated that the internal solar magnetic fields could produce instabilities in the solar plasma. 3. ...holds that Milankovitch cycles can induce changes in solar heating on Earth and the changes are amplified on Earth. 4. ...doesn't believe in Ehrlich's viewpoints at all. Questions 5-9 Do the following statements agree with the information given in the reading passage? In boxes 5-9 on your answer sheet write TRUE if the statement is true according to the passage FALSE if the statement is false according to the passage NOT GIVEN if the information is not given in the passage 5. The ice ages changed frequency from 100,000 to 41,000 years a million years ago. 6. The sole problem that the Milankovitch theory can not solve is to explain why the ice age frequency should shift from one to another. 7. Carbon dioxide can be locked artificially into sea ice to eliminate the greenhouse effect. 8. Some scientists are not ready to give up the Milankovitch theory though they haven't figured out which mechanisms amplify the changes in solar heating. 9. Both Edwards and Ehrlich believe that there is no practical way to test when the solar temperature oscillation begins and when ends. Questions 10-14 Complete the notes below. Choose one suitable word from the Reading Passage above for each answer. Write your answers in boxes 10-14 on your answer sheet. The standard view assumes that the opposing pressures of gravity and nuclear fusions hold the temperature ...10...in the sun's interior, but the slight changes in the earth's ...11... alter the temperature on the earth and cause ice ages every 100,000 years. A British scientist, however, challenges this view by claiming that the internal solar magnetic ...12... can induce the temperature oscillations in the sun's interior. The sun's core temperature oscillates around its average temperature in ...13... lasting either 100,000 or 41,000 years. And the ...14... interactions within the sun's magnetic field could flip the fluctuations from one cycle length to the other, which explains why the ice ages changed frequency a million years ago.
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Selling Digital Music without Copy-protection Makes Sense A.　It was uncharacteristically low-key for the industry’s greatest showman. But the essay published this week by Steve Jobs, the boss of Apple, on his firm’s website under the unassuming title “Thoughts on Music” has nonetheless provoked a vigorous debate about the future of digital music, which Apple dominates with its iPod music-player and iTunes music-store. At issue is “digital rights management” (DRM)—the technology guarding downloaded music against theft. Since there is no common standard for DRM, it also has the side-effect that songs purchased for one type of music-player may not work on another. Apple’s DRM system, called FairPlay, is the most widespread. So it came as a surprise when Mr. Jobs called for DRM for digital music to be abolished. B.　This is a change of tack for Apple. It has come under fire from European regulators who claim that its refusal to license FairPlay to other firms has “locked in” customers. Since music from the iTunes store cannot be played on non-iPod music-players (at least not without a lot of fiddling), any iTunes buyer will be deterred from switching to a device made by a rival firm, such as Sony or Microsoft. When French lawmakers drafted a bill last year compelling Apple to open up FairPlay to rivals, the company warned of “state-sponsored piracy”. Only DRM, it implied, could keep the pirates at bay. C.　This week Mr. Jobs gave another explanation for his former defence of DRM: the record companies made him do it. They would make their music available to the iTunes store only if Apple agreed to protect it using DRM. They can still withdraw their catalogues if the DRM system is compromised. Apple cannot license FairPlay to others, says Mr Jobs, because it would depend on them to produce security fixes promptly. All DRM does is restrict consumer choice and provide a barrier to entry, says Mr Jobs; without it there would be far more stores and players, and far more innovation. So, he suggests, why not do away with DRM and sell music unprotected? “This is clearly the best alternative for consumers,” he declares, “and Apple would embrace it in a heartbeat.” D.　Why the sudden change of heart? Mr Jobs seems chiefly concerned with getting Europe’s regulators off his back. Rather than complaining to Apple about its use of DRM, he suggests, “those unhappy with the current situation should redirect their energies towards persuading the music companies to sell their music DRM-free.” Two and a half of the four big record companies, he helpfully points out, are European-owned. Mr Jobs also hopes to paint himself as a consumer champion. Apple resents accusations that it has become the Microsoft of digital music. E.　Apple can afford to embrace open competition in music players and online stores. Consumers would gravitate to the best player and the best store, and at the moment that still means Apple’s. Mr Jobs is evidently unfazed by rivals to the iPod. Since only 3% of the music in a typical iTunes library is protected, most of it can already be used on other players today, he notes. (And even the protected tracks can be burned onto a CD and then re-ripped.) So Apple’s dominance evidently depends far more on branding and ease of use than DRM-related “lock in”. F.　The music giants are trying DRM-free downloads. Lots of smaller labels already sell music that way. Having seen which way the wind is blowing, Mr Jobs now wants to be seen not as DRM’s defender, but as a consumer champion who helped in its downfall. Wouldn’t it lead to a surge in piracy? No, because most music is still sold unprotected on CDs, people wishing to steal music already can do so. Indeed, scrapping DRM would probably increase online-music sales by reducing confusion and incompatibility. With the leading online store, Apple would benefit most. Mr Jobs’s argument, in short, is transparently self-serving. It also happens to be right. Notes to Reading Passage 1 1. low-key: 抑制的，受约束的，屈服的 2. showman: 开展览会的人, 出风头的人物 3. unassuming: 谦逊的, 不夸耀的, 不装腔作势的 4. iPod： (苹果公司出产的)音乐播放器 5. iTunes store： (苹果公司出产的)在线音乐商店 6. get off person’s back: 不再找某人的麻烦，摆脱某人的纠缠 7. gravitate: 受吸引，倾向于 8. unfazed: 不再担忧，不被打扰 Questions 1-7 Do the following statemets reflect the claims of the writer in Reading Passage 1? Write your answer in Boxes 1-7 on your answer sheet. TRUE if the statement reflets the claims of the writer FALSE if the statement contradicts the claims of the writer NOT GIVEN if it is impossbile to say what the writer thinks about this 1. Apple enjoys a controlling position in digital music market with its iPod music-player and iTunes music-store. 2. DRM is a government decree issued with a purpose to protect downloaded music from theft by consumers. 3. Lack of standardization in DRM makes songs bought for one kind of music player may not function on another. 4. Apple has been criticized by European regulators since it has refused to grant a license FairPlay to other firms. 5. All music can be easily played on non-iPod music devices from Sony or Microsoft without too much fiddling. 6. Apple depends far more on DRM rather than branding for its dominance of the digital music devices. 7. If DRM was cancelled, Sony would certainly dominate the international digital music market. Questions 8-10 Choose the appropriate letters A-D and write them in boxes 8-10 on your answe sheet. 8. Which of the following statements about Mr. Jobs’ idea of DRM is NOT TRUE? A. DRM places restrictions on consumer’ choice of digital music products available. B. DRM comples iTunes buyers to switch to a device made by Sony or Microsoft. C. DRM constitutes a barrier for potential consumers to enter digital music markets. D. DRM hinders development of more stores and players and technical innovation. 9. The word “unfazed” in line 3 of paragraph E, means___________. A. refused B. welcomed C. not bothered D. not well received 10. Which of the following statements is TRUE if DRM was scapped? A. Sony would gain the most profit. B. More customers would be “locked in”. C. A sudden increase in piracy would occur. D. Online-music sales would probably decrease. Questions 11-14 Complete the notes below. Choose NO MORE THAN THREE WORDS from Reading Passage 1 for each answer. Write your answers in boxes 11-14 on your answer sheet. Mr. Steve Jobs, the boss of Apple, explains the reason why he used to defend DRM, saying that the company was forced to do so: the record companies would make their music accessible to …11...only if they agreed to protect it using DRM; they can still…12…if the DRM system is compromised. He also provides the reason why Apple did not license FairPlay to others: the company relies on them to …13….But now he changes his mind with a possible expectation that Europe’s regulators would not trouble him any more in the future. He proposes that those who are unsatisfactory with the current situation in digital music market should …14… towards persuade the music companies to sell their music DRM-free.