劍橋雅思9Test3閱讀Passage3原文翻譯information theory–the big idea

劍橋雅思9Test3閱讀Passage3原文翻譯information theory–the big idea，今天中國教育在線就來為大家分析這個問題。

information theory–the big idea

信息理論

劍橋雅思9 Test3 Passage3閱讀原文翻譯

引言

Information theory lies at the heart of everything—from DVD players and the genetic code of DNA to the physics of the universe at its most fundamental.It has been central to the development of the science of communication,which enables data to be sent electronically and has therefore had a major impact on our lives

信息理論是一切的核心-從DVD播放機和DNA的遺傳密碼到最根本的宇宙物理學。它一直是傳播學發(fā)展的核心所在。它使數(shù)據(jù)能夠以電子方式發(fā)送，并因此已經(jīng)對我們的生活產(chǎn)生重大影響

段落A

In April 2002 an event took place which demonstrated one of the many applications of information theory.The space probe Voyager I,launched in 1977,had sent back spectacular images of Jupiter and Saturn and then soared out of the Solar System on a one-way mission to the stars.After 25 years of exposure to the freezing temperatures of deep space,the probe was beginning to show its age.Sensors and circuits were on the brink of failing and NASA experts realized that they had to do something or lose contact with their probe forever.The solution was to get a message to Voyager I to instruct it to use spares to change the failing parts.With the probe 12 billion kilometers from Earth,this was not an easy task.By means of a radio dish belonging to NASA’s Deep Space Network,the message was sent out into the depths of space.Even travelling at the speed of light,it took over 11 hours to reach its target,far beyond the orbit of Pluto.Yet,incredibly,the little probe managed to hear the faint call from its home planet and successfully made the switchover.

2002年4月發(fā)生了一起事件。它證明了信息理論的許多應用之一。于1977年發(fā)射升空的“旅行者1號”太空探測器文章來自老烤鴨雅思送回了木星和土星的壯觀影像，然后飛離太陽系執(zhí)行探索恒星的單程任務。暴露于深空的冰凍溫度25年后，該探測器開始老化。傳感器和電路位于崩潰的邊緣。NASA專家意識到他們必須做些什么，否則的話就會永遠與探測器失去聯(lián)系。解決辦法是向旅行者1號發(fā)送一條消息，指示其使用備用零件更換出現(xiàn)故障的零件?？紤]到探測器距地球有120億公里，這并非易事。通過屬于NASA深空網(wǎng)絡的無線電天線，該消息被發(fā)送到太空深處。即使以光速行進，也花了11個多小時才能到達目標，遠遠超出冥王星的軌道。然而，令人難以置信的是，這一小型探測器設法聽到了來自其母星的微弱聲音，并成功進行了轉換。

段落B

It was the longest-distance repair job history,and a triumph for the NASA engineers.But it also highlighted the astonishing power of the techniques developed by American communications engineer Claude Shannon,who had died just a year earlier.Born in 1916 in Petoskey,Michigan,Shannon showed an early talent for maths and for building gadgets and made breakthroughs in the foundations of computer technology when still a student.While at Bell Laboratories,Shannon developed information theory but shunned the resulting acclaim.In the 1940s,he single-handedly created an entire science of communication which has since inveigled its way into a host of applications,from DVDs to satellite communications to bar codes—any area,in short,where data has to be conveyed rapidly yet accurately.

這是歷史上跨越最長距離的修理，也是NASA工程師的勝利。但是，它也突顯了一年前去世的美國通信工程師克勞德·香農(nóng)（Claude Shannon）所開發(fā)的技術的驚人力量。香農(nóng)于1916年在密歇根州的佩托斯基（Petoskey）出生。他從小就展現(xiàn)出數(shù)學和搭建小工具方面的天賦，并在還是學生的時候就在計算機技術的基礎上取得了突破。在貝爾實驗室時，香農(nóng)提出了信息理論，但回避了由此產(chǎn)生的好評。在20世紀40年代，他一手創(chuàng)建了后來應用于各種領域的通信科學，從DVD到衛(wèi)星通訊再到條形碼。簡言之，任何需要對信息進行快速而準確的傳輸?shù)念I域。

段落C

This all seems light years away from the down-to-earth uses Shannon originally had for his work,which began when he was a 22-year-old graduate engineering student at the prestigious Massachusetts Institute of Technology in 1939.He set out with an apparently simple aim:to pin down the precise meaning of the concept of‘information’.The most basic form of information,Shannon argued,is whether something is true or false—which can be captured in the binary unit,or‘bit’,of form 1 or 0.Having identified this fundamental unit,Shannon set about defining otherwise vague ideas about information and how to transit it from place to place.In the process he discovered something surprising:it is always possible to guarantee the information will get through random interference—‘noise’—intact.

這一切似乎與香農(nóng)最初的應用相差很遠。1993年他22歲，是著名的麻省理工學院工程學的研究生。他一開始的目的很簡單：確定“信息”這一概念的確切含義。香農(nóng)認為，基本的信息形式是判斷事物正確與否，這可以用二進制單位“比特”以1或者0的形式來記錄。香農(nóng)確定了此基本形式后，便著手定義關于信息和信息跨地區(qū)傳輸?shù)钠渌：拍?。在這個過程中，他發(fā)現(xiàn)了一些令人吃驚事情：總是有可能使信息穿過隨機的干擾-噪音-而保持完整。

段落D

Noise usually means unwanted sounds which interfere with genuine information.Information theory generalizes this idea via theorems that capture the effects of noise with mathematical precision.In particular,Shannon showed that noise sets a limit on the rate at which information can pass along communication channels while remaining error-free.This rate depends on the relative strengths of the signal and noise travelling down the communication channel,and on its capacity(its‘bandwidth’).The resulting limit,given in units of bits per second,is the absolute maximum rate of error-free communication given signal strength and noise level.The trick,Shannon showed,is to find ways of packaging up—‘coding’—information to cope with the ravages of noise,while staying within the information-carrying capacity—‘bandwidth’—of the communication system being used.

噪音通常表示會干擾到真正信息的多余聲音。信息理論通過定理概括了這一概念。它以數(shù)學的精確度確定了噪聲的影響。更確切的說，香農(nóng)表示噪音在速度方面存在限制。在特定的速度上，信息可以通過通信頻道并保持完整。該速度單位為比特/秒，是在給定的信號強度和噪音水平下，信息無誤差傳送的最大絕對速度。香農(nóng)指出，提供這一速度的有效方法是在所使用的通信系統(tǒng)的傳送能力（即帶寬）范圍內(nèi)，找到將信息打包（即編碼）的方式，來應對噪聲的破壞。

段落E

Over the years scientists have devised many such coding methods,and they have proved crucial in many technological feats.The voyager spacecraft transmitted data using codes which added one extra bit for every single bit of information;the result was an error rate of just one bit in 10,000—and stunningly clear pictures of the planets.Other codes have become part of everyday life—such as the Universal Product Code,or bar code.Which uses a simple error-detecting system that ensures supermarket check-out lasers can read the price even on,say,a crumpled bag of crisps.As recently as 1993,engineers made a major breakthrough by discovering so-called turbo—which come very close to Shannon’s ultimate limit for the maximum rate that data can be transmitted reliably,and now play a key role in the mobile videophone revolution.

多年來，科學家們已經(jīng)設計出許多這樣的編碼方法，也證明了它們對許多技術成就至關重要。旅行者號航天器利用編碼傳輸數(shù)據(jù)，這些編碼在每比特信息上都額外增加了一比特信息，使錯誤率僅為萬分之一，得到清晰度驚人的行星圖片。其他編碼已成為日常生活的一部分，例如通用產(chǎn)品代碼或條形碼。它使用一種簡單的錯誤檢測系統(tǒng)，確保超市的激光結賬設備甚至可以在皺巴巴的薯片袋上讀取價格。就在1993年，工程師們?nèi)〉昧艘豁椫卮笸黄?，發(fā)現(xiàn)所謂的Turbo碼，這與香農(nóng)提出的信息可以安全傳送的最大速度極限非常接近?，F(xiàn)在，Turbo碼在移動可視電話變革中發(fā)揮著關鍵的作用，

段落F

Shannon also laid the foundations of more efficient ways of storing information,by stripping out superfluous(‘redundant’)bits from data which contributed little real information.As mobile phone text messages like‘I CN C U’show,it is often possible to leave out a lot of data without losing much meaning.As with error correction,however,there’s a limit beyond which message become too ambiguous.Shannon showed how to calculate this limit,opening the way to the design of compression methods that cram maximum information into the minimum space.

通過去除含有較少真實信息的多余數(shù)據(jù)，香農(nóng)也會開發(fā)更有效率地儲存信息的方式奠定了基礎。正如手機短信“I CN C U”（I can see you的縮寫）一樣，有可能在省略了很多數(shù)據(jù)之后，基本意思保持不變。但是，正如糾錯一樣，省略存在一定的限制。超過該限制信息就會變得模糊不清。香農(nóng)說明了如何計算這一限制，為設計信息壓縮方法，從而將最多的信息塞進最小的空間開辟了道路。

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