Nearly ideal binary communication in squeezed channels

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高三英语学术成果单选题50题

高三英语学术成果单选题50题1. In the scientific research paper, the new discovery was described as "a ______ breakthrough that could change the future of medicine."A. crucialB. criticalC. acuteD. severe答案：A。

本题考查词汇辨析。

crucial表示至关重要的，在描述突破对医学未来的影响时，表达其关键重要性；critical也有批判的、关键的意思，但更多用于批判性的情况或危机时刻，在这里不如crucial合适；acute主要指尖锐的、敏锐的或者急性的（疾病等），与语境不符；severe表示严重的，多形容程度恶劣，不适用于描述突破的重要性。

2. The history article mentioned that during the war, the city faced a ______ shortage of food.A. severeB. strictC. rigidD. stern答案：A。

解析：severe表示严重的，用来形容食物短缺的程度非常严重，符合语境；strict侧重于严格的，常指规定、纪律等严格；rigid表示僵硬的、死板的，多形容物体或者规则缺乏灵活性；stern主要指严厉的，多形容人的态度，这三个选项均不符合食物短缺的语境。

3. In the literary analysis, the author's use of symbolism was very ______, adding deep meaning to the story.A. subtleB. delicateC. faintD. weak答案：A。

答案解析：subtle表示微妙的、隐晦的，在文学分析中，作者对象征手法的使用很微妙，给故事增添深意，是合适的表达；delicate指精致的、娇弱的，更多形容物体的外观或者人的身体状况等；faint表示微弱的、模糊的，多形容声音、光线等；weak表示虚弱的、薄弱的，不适合形容象征手法的运用。

武汉大学新闻学院专业英语题库有答案喔讲解

Chapter 11.The communication process is initiated（开始）by the:A)message B)receiver C)source D)channel2.The interpretation解释of physical message into a form that has eventual最后的meaning for a receiver is called:A)coding B)recoding C)decoding D)encoding3.Receivers can be:A)a group B)a single person C)an institution机构D)all of these4.An increase in noise _________ message fidelity保真度，精确.A)increases B)decreases C)does not affect D)expands5.In machine-assisted机器辅助interpersonal communication人际传播:A)source and receiver can be separated by time and spaceB)messages can have permanence永久性C)messages can be amplified扩大的or transmitted传输over large distancesD)all of these6.Mass communication refers to the process by which a complex organization with the aid of one or more machines produces and transmits public messages that are directed at large, scattered分散的audiences that are:A)heterogeneous多样性B)homogenous同质的C)related有关联的D)specific 特定特殊7.Message termination is easiest in:A)interpersonal communicationB)mass communicationC)machine-assisted interpersonal communicationD)none of these8.Mass communication organizations:A)have multiple gatekeepersB)require little money to operateC)exist regardless of profitD)are non-competitive9.The following is an example of a media vehicle工具，媒介:A)newspapers and magazines B)radio stations C)TV networks D)All of these10 Disintermediation eliminates theA) source B) middleman C) customer D) seller10.In a communication setting, encoding may take place only once.A)True B)False11.Encoding becomes less important in machine-assisted interpersonal communication.A)True B)False12.Interpersonal communication can occur between two people without being in each other's physical presence.A)True B)False13.The receiver in the machine-assisted setting can be a single person only.A)True B)False14.The term mass media refers to the messages carried to the public by vehicles such as TV, radio, and magazines, and the Internet.A)True B)False15.Examples of user-generated content include YouTube, MySpace, Flickr, and Wikipedia.A)True B)False16.The emerging trends新兴趋势in mass communication are audience segmentation分割, convergence聚合融合, disintermediation非居间化脱媒, increasing audience control, and multiple platforms.A)True B)FalseChapter 21.An advantage of the functional approach功能学说to studying mass communication is that it:A)provides a perspective 远景，观点to examine mass communication relaxation放松缓和B)generates 生成concepts that are helpful in understanding media behaviorC)makes us aware of the diversity of gratifications满意喜悦provided by the mediaD)all of these2.Harmful or negative consequences of the functions of mass media are called:A)afflictions 苦难折磨B)ramifications分叉C)dysfunctions机能障碍D)displacement取代3.Which of the following is an important factor in determining which news medium people find most believable?A)convenience B)comfort C)credibility D)format格式4.The concept representing the idea that if the audience believes you really matter, you will be the focus of media attention, and if you are the focus of media attention, then you really matter is known as:A)hype（皮下注射理论）B)status conferral 地位授予C)primacy/latency首要性/潜伏期D)priming启动效应5.When reading the Washington Post, a person is most likely utilizing利用the ________ function of the media.A)surveillance 监测B)interpretation 解释，翻译C)linkage D)transmission of values6.Telethons, eBay, and chat rooms are examples of:A)surveillance B)linkage C)interpretation D)transmissionics连环画, puzzles游戏拼图, horoscopes星座, games, advice, gossip, humor, and general entertainment account for which percentage of newspaper content?A)6 B)12 C)18 D)248.___________ is a form of diversion.A)stimulation刺激鼓舞B)relaxation放松消遣C)emotional release情绪缓解D)all of these9.Developing feelings of kinship 亲属关系with media characters is known as a __________ relationship.A)social B)parasocial类社会性的C)cathartic泻剂D)paranormal超常的10.The creation of unstable superior不稳定的优势and inferior positions 劣势that are continuously being negotiated 商谈through interpretations解释of meaning is known as:A)culture B)ideology意识形态C)hegemony 霸权D)ascendancy优势，支配地位11.The four categories of the uses and gratifications model are（使用与满足理论的四个方面）:A)cognition认知, diversion转移, sociality utility社会功能, and withdrawal撤退B)function, dysfunction, malfunction, and cognitionC)surveillance, consequences, credibility, and interpretationD)none of these12.The news and information role of the media is known as surveillance.A)True B)False13.The media sometimes consciously try to instill灌输values and behavior in the audience through their portrayal of society社会写照.A)True B)False14.At the individual or micro level, the functional approach is called the uses-and-gratifications model.A)True B)False15.Feminist scholars are more likely to be drawn to the functional approach than to the critical cultural approach.A)True B)False16.The critical/cultural approach is interested in the meaning of media content for audiences.A)True B)False14 The critical/cultural studies approach is based on asking people questions, tabulating their results, and enumerating characteristics of media content.批判研究是基于问人问题,制表结果分析,列举媒体内容的特征A) true B) false15 The critical/cultural approach is more useful than the functional approach in understanding the complicated relationship between mass communication and its audience.批判研究比功能更有用的方法理解大众传播与观众之间的复杂关系A) true B) falseChapter 31.The following is an example of an early form of paper:A)clay tablets 泥版B)papyrus纸莎草C)parchment羊皮纸D)all of these2.During the feudal period封建时期in Europe, bookmaking became centered in:A)libraries B)tax offices C)monasteries修道院D)wineries3.The moveable metal type printing press was developed by:A)Martin Luther B)Samuel Morse C)Matthew Brady D)Johann Gutenberg4.The first medium to use digital communication was:A)radio B)television C)printing press D)telegraph5.The invention of the ____________ led to the development of what we would today call news.A)radio B)television C)printing press D)telegraph6.Which invention was the first to be called "the great annihilator歼灭者of time and space?"A)radio B)television C)printing press D)telegraph occupies more time than any other activity outside of work and sleep with the average set on for:A)four hours a day B)eight hours a day C)twelve hours a day D)sixteen hours a day8.The long-range impact of the motion picture lay mainly in the areas of:A)news and reporting B)business and the law C)entertainment and culture D)all of these9.The first mass medium that brought sports, music, talk, and news into the living room was the:A)telegraph B)radio C)telephone D)newspaper10.The technology behind television received a substantial boost from which war's efforts?A)The Civil War B)WWI C)WWII D)all of these4 Most early books were written inA) Latin B) English C) French D) German7 The inventor that helped the development of photography was:A) Louis Daguerre B) William Fox Talbot C) George Eastman D) All of the above11.Digital technology encodes information such as sound, text, data, graphics, and video into a series of on and off pulses that are usually denoted as ones and twos（应该是0和1）.A)True B)False12.The telegraph was revolutionary because it enabled people to communicate in real time over vast distances.A)True B)False13.Technological determinism 技术决定论is the belief that technology drives historical change.A)True B)False14.The Civil War was the first American war to be photographed intensely.A)True B)False15.The characteristics of mobile media include wireless technology available virtually everywhere, and interconnectivity.A)True B)False16.The seven milestones in the development of human communication are: printing, telegraph and telephone, photography and motion pictures, radio and television, digital media, mobile media, and social media.A)True B)FalseChapter 41.The first American newspaper was:A)the Boston News Letter B)Publick Occurrences both Foreign and DomestickC)New England Courant D)Pennsylvania Gazette2.Benjamin Franklin is credited with:A)starting the Pennsylvania Gazette宾夕法尼亚公报B)running the first editorial cartoonC)demonstrating that journalism could be an honorable profession D)all of these3.The freedom of the press is protected by:A)the First Amendment B)the Fifth AmendmentC)the original Constitution D)the Declaration of Independence4.The first penny press paper, the New York Sun, was popular because it contained:A)political debates and an aggressive editorial policy B)a sports page and a financial pageC)local stories of sex, violence, features, and human interest stories D)all of these5.The Penny Press changed:A)the basis of economic support for newspapers B)the pattern of distributionC)the definition of what constituted news and how it was collected D)all of these6.The idea of a newspaper chain was pioneered by:A)Joseph Pulitzer B)E.W. Scripps C)William Randolph Hearst D)Horace Greeley7.Although the onset of yellow journalism in the U.S. was not the proudest moment in American newspaper history, it did help bring about:A)aggressive reporting and investigative stories B)more enthusiasm and verve in the professionC)the onset of more professional writing D)all of these8.Jazz journalism is characterized by which of the following features?A)most centrally located in New York, B)were tabloid size,C)made lavish浪费的，丰富的use of photographs, D)all of these9.Characteristics of online newspapers include:A)can be continuously updated B)interactive and feature user-generated contentC)limited by newshole sizeD)can be continuously updated and interactive and feature user-generated content.7Although the onset of yellow journalism in the U.S. was not the best moment in American newspaper history, it did help bring aboutA)aggressive reporting and investigative storiesB) the use of layout布局and display devicesC) wide exposure form many prominent突出的authorsD) all of the above8 Jazz journalism is characterized by which of the following featuresA) the use of tabloids B) an abundance 充裕，丰富of photographsC) both A and B D) none of the above9 According to the text, one result of a credibility scandal in newspapers, such as the Jayson Blair saga was thatA) editors refuse to reveal 揭露泄露their ethical guidelines to the publicB) online news reporting becomes more reliableC) newspapers stiffened加强their requirements for quotes引用from unnamed sourcesD) college journalism programs decline to teach ethics to students10 Newspapers are trying to attract more readers byA) using more colorB) creating highlighted synopses概要within long storiesC) printing more lifestyle and fashion featuresD) all of the above10.In journalism, a newshole新闻版面is the amount of news that a paper prints in each edition. It remains the same until the publisher decides to change it.A)True B)False11.Increased competition, credibility crisis危机, and changing social and economic conditions have contributed to the decline 衰退in newspaper circulation流通，发行量.A)True B)False12.In addition to the Internet, newspapers are distributing分散，分配news via mobile media such as Internet-enabled授权，激活cell phones, personal digital assistants (PDAs), and laptops.A)True B)False13.Gannett甘尼特is the biggest newspaper group.A)True B)False14."Blog" is short for "web log" and exists in the "blogosphere."A)True B)False15.A blog is a website that contains an online personal journal with reflections, comments, and hyperlinks.A)True B)False16.A replica复制品edition of a newspaper has the same design as the print edition.A)True B)FalseChapter 51.The number of magazines produced increased from 1860—1900 because of:A)money from investors投资者B)better printing techniquesC)the Postal Act of 1879 邮政法案D)all of these2.A popular magazine that began publishing in the late 1930s and continued to publish until it expired过期失效in 1972 was:A)Look B)Leslies C)The San Francisco Wasp D)all of these3.Between WWI and WWII, the shift in economic development and change in lifestyles influenced the development of the:A)digest文摘B)news magazine C)pictorial magazine 画报D)all of these4.Magazines use their websites for all of the following except:A)to provide additional information about stories B)subscriptions订阅，捐献，服务C)production D)e-commerce电子商务5.According to the text, magazines are distinguished 杰出from other media in that they:A)attract the highest number of consumersB)attract the most specialized audiencesC)give the most in depth news coverageD)provide the most content for the cost6.The magazine industry is divided by the following function categories except:A)production B)distribution C)retail零售D)advertising7.Controlled circulation magazines gain most of their revenue收益from:A)subscriptions订阅B)advertising C)e-commerce D)single-copy sales8.The following division heads report to the circulation director 发行量主管except:A)Managing Editor 总编辑B)Subscription订阅ManagerC)Single-Copy Sales Manager 单份销售D)Subscription Fulfillment Director订阅实现9.In addition to ancillary附属品，助手services such as e-commerce, custom publishing定向出版, and database assistance辅助, which of the following is another basic source of magazine revenue?A)subscriptions B)single-copy sales C)advertising D)all of these10.Data on the total audience for magazines gathered by conducting personal interviews with individuals to get an exposure score风险评分is provided byA)Audit Bureau of Circulation (ABC)B)Business Publication Audit (BPA)C)Mediamark Research Inc (MRI)D)Nielsen/NetRatings11.A magazine's rate base is the number of buyers guaranteed by a magazine.A)True B)False12.Hemispheres, an in-flight magazine, is an example of a controlled circulation magazine.A)True B)False13.Most adults read at least one magazine a month.A)True B)False14.A magazine dummy样本，仿制品is the schedule drawn up to ensure that articles get to the printer in time for the forthcoming issue下期预告.A)True B)False15.Mobile magazines can be read on laptops笔记本电脑, cell phones, and PDAs.A)True B)False16.Magazines publishers have turned their attention to increasing circulation in other countries, targeting trends, and looking for creative ways to deliver magazines electronically.A)True B)False11 Magazine readers are usually loners.A) true B) false12 Benjamin Franklin published the first American magazine.A) true B) false13 Custom publications are often offered for free at business locations.A) true B) false15 Newsletters时事通讯are characterized by their general readership, large circulation, and low prices.A) true B) falseChapter 61.In 1455, the first book Johann Gutenberg printed on a moveable metal type press was a(n):A)dictionary B)encyclopedia 百科全书C)bible圣经D)atlas地图2.The commercialization of publishing was brought about by: P133A)agents negotiating 谈判the best bottom lineB)houses publishing popular works of fictionC)a sluggish萧条economy forcing houses to depend on banksD)all of these3.Digital books are known as:A)MyBooks B)e-books C)iBooks D)digital books4.An advantage of printing on demand按需印刷is: P136A)the elimination消除，除去of expensive production and shipping 运输costsB)publishers can make money on books that sell only a few hundred copiesC)special interest books can now be printed that would have been too expensive to publish with the traditional methodD)all of these5.The book publishing industry is divided into 3 segments:A)publishers出版人, distributors配销商, and retailers零售商B)trade, religious, and professionalC)mail order, college, and audiovisualD)fiction, nonfiction, religious6.The world's largest educational publisher is:A)McGraw Hill B)Time-Warner Publishing C)Pearson Publishing D)Thompson/Wadsworth7.Type style, composition, paper, printing, and binding are the responsibility of which publishing department?A)editorialB)productionC)marketingD)general administration (or business)8.Editors acquire books from the following source:A)agents B)authors C)their own ideas D)all of these9.The main source of publishing income is:A)book sales and subsidiary rights 附属法例B)foreign marketsC)e-commerceD)marketing and editorial production10.The most important form of audience feedback反馈in the book industry comes from:A)BPA B)MRI C)Best-Seller Lists D)Niesen BookScan11.Studies show that book reading is not tied to相关联income or education.A)True B)False12.The paperback平价本boom of the 1880s prompted the adoption of a new copyright law.A)True B)False13.After World War II, expanded leisure闲暇time and more disposable可任意处理的income made book reading a popular means of recreation娱乐.A)True B)False14.Books are one of the most "mass" of the mass media.A)True B)False15.Advances and acquisition rights are two of the big expenses in publishing.A)True B)False16.A recent survey found the biggest increase in literary reading was among 18- to 24-year-olds.A)True B)FalseChapter 71.The first radio station was developed by:A)Heindrich HertzB)Reginald FessendenC)David SarnoffD)Frank Conrad2.The idea to sell broadcasting time on the radio for advertising is credited to:A)A T&T B)RCA C)Westinghouse D)NBC3.The first network was:A)Westinghouse B)AT & T C)NBC D)CBS4.Established by the Radio Act of 1927, the Federal Radio Commission (FRC):A)defined the AM broadcast bandB)standardized channel designationsC)minimized interferenceD)all of these5.Frequency modulation radio (FM) was invented by:A)David SarnoffB)Edwin Howard ArmstrongC)Frank ConradD)Edward R. Murrow6.A characteristic of digital radio broadcasting will be:A)ability to broadcast multiple programs simultaneously同时地B)static-free signals不受静电干扰的信号C)compatibility兼容性with analog模拟signalsD)all of these7.Noncommercial stations are supported by all of the following, except:A)listener donationsB)Corporation for Public Broadcasting (CPB)C)advertisementsD)endowments and grants from foundations8.The person responsible for the sound of the station through music and other material is called the:A)acoustics manager音响B)resonance technician 共振技术C)frequency programmer频率程序员D)program director9.Which source of advertising income represents the largest portion of revenue?A)national ads B)national spot ads C)local ads D)international ads10.The major company that measures radio audiences is:A)BPA B)Arbitron C)MRI D)Nielsen Media Research8The people responsible for the sound of the station through music and other material are part of the following department:A)sales B)program C)news D)engineering9Which source of advertising income represents the largest portion部分of revenue?A)national B)regional C)local D) none of the above11.Many early radio stations were not owned by broadcasters.A)True B)False12.Radio was able to weather经受the Depression with relatively little hardship.A)True B)False13.Radio was not financially affected by the development of television.A)True B)False14.Many conservative保守的talk show hosts have been successful in radio.A)True B)False15.Clear Channel Communications is the largest radio company in terms of advertising revenue.A)True B)False16.The rise of IPods and MP3 players has led to a new form of content called "podcasting."A)True B)False13Radio was unaffected不受影响的by the development of television.A) trueB) false14Many liberal talk show hosts have been successful in radio.A) trueB) false15Infinity is the largest radio company.A) trueB) falseChapter 81.The first disk player 唱片机designed to look like a piece of furniture was the:A)Electro-Magnetic PhonographB)gramophoneC)VictrolaD)phonautograph2.The Beatles are credited with:A)introducing the harmonica 口琴as a rock instrumentB)changing the shape of the music business and American popular cultureC)paving the way for the "British Invasion"铺平道路D)all of these .3.Once the recording industry switched from __________ technology, it became vulnerable to illegal file-sharing.A)broadcast to Internet B)analog to digital 模拟C)broadcast to satellite 卫星D)analog to electronic4.Some of the effects the iPod has had include:A)podcasts 播客B)a cultural impactC)empowering the audience member to take more control of the mass communication experienceD)all these5.The greatest number of total sales in the record industry is accounted for by:A)country B)r&b C)rap D)rock6.The "Talent" category of the recording industry includes all of the following except:A)singers B)sound technicians C)songwriters D)musicians7.Of all the outlets for tape and CD distribution, retail stores and rack jobbers account for which percentage of all sales?A)80 B)60 C)40 D)208.The symbol used in the Billboard charts, the most important channel of feedback in the sound recording industry, is:（答案不一样）A)stars B)triangles 三角铁C)bullets 子弹D)all of these9.Which percentage of households in the country has some means of playing a record唱片, tape 磁带, or CD?A)100 B)90 C)80 D)7010.Buyers under 30 account for the majority of record purchases.A)True B)False11.During the Depression years, sound recording was bolstered 支撑with the help of coin-operated 投币record players called jukeboxes.A)True B)False12.A demonstration 示范tape, or demo, needs to sound as good as the finished product released by the studio.A)True B)False13.The recording industry is one of the most concentrated of all media industries.A)True B)False14.The Billboard charts play an important part in the feedback mechanism for sound recording.A)True B)False15.The four companies that dominate控制the recording industry are UMG, BMG, EMI, and Warner Music.A)True B)False12After the repeal of Prohibition, sound recording was bolstered with the help of coin-operated record players called jukeboxes.A) trueB) false14A new artist generally receives a royalty rate of about 25 per cent of the suggested retail price ofa CD or cassette.A) trueB) False3.Since the beginning of the 21st century, the recording industry has tried to stifle file-sharing services by all the following means exceptA) threatening to sue file sharersB) discouraging artists from using band websitesC) setting up their own digital music servicesD) exploring technical devices that make it difficult to copy files4MP3 is an abbreviation forA) Music Production Audio Layer 3B) Movie Production Group Audio Layer 3C) Motion Pictures Engineering Group Audio Layer 3D) none of the above8In the process of making a CD, the next step after the recording session isA) laying down tracksB) reproducing the masterC) the mixdownD) promotionChapter 91.What happens when a person sees one light source go out while another one close to the original is illuminated照明启发is referred to as:A)phiphenomenon 似动现象B)persistence of vision 持续视觉？C)perception phenomenon D)extra-Sensory Perception 第六感2.The first practical motion picture camera and viewing device was developed by:A)George and Noble JohnsonB)Joseph Niepce and Louis DaguerreC)Thomas Edison and William DicksonD)Reginald Fessenden and Lee De Forest3.The Motion Picture Patents Company (MPPC) was formed in order to:A)create filmmaker bill of rightsB)create new innovations in movie making technologyC)restrict moviemaking to just nine companiesD)censor salacious content4.The first film that featured sound was:A)A Trip to the Moon B)Birth of a NationC)The Great Train Robbery D)The Jazz Singer5.The film industry fought back against television by:A)refusing to advertise their films on televisionB)withholding old films for showing on televisionC)forbidding their stars from appearing on televisionD)all of these6.The main disadvantage of digital distribution is:A)picture and audio qualityB)the loss of "movie feel"C)most theaters are not yet equipped for it due to costD)that filmmakers are against it7.Which division of the film industry is responsible for supplying prints of films to theaters?A)production B)distribution C)exhibition D)postproduction后期制作8.The average shooting schedule for the typical film is:A)30 days B)70 days C)100 days D)130 days9.Frequent moviegoers are usually all of the following except:A)young B)middle class C)married D)from an urban area10.Movie attendance declined drastically剧烈throughout World War II.A)True B)False11.Cinemascope, Panavision宽荧幕电影, and Vistavision全景are credited with saving Hollywood's loss of money to television.A)True B)False12.Revenues from the sale and rental of videocassettes and DVDs, and from pay-per-view and premium cable have been greater than revenues from movie theater admissions.A)True B)False13.Motion pictures are the most expensive media product to produce.A)True B)False14.At some theaters, concession sales represent up to 90 percent of the profits.A)True B)False15.The biggest concern facing the motion picture industry is illegal file sharing.A)True B)FalseChapter 101.In 1945 there were only eight television stations and 8,000 homes with TVs. How many years did it take for there to be 100 stations and 35 million TV households?A)40 B)45 C)35 D)102.Television's early programming structure was modeled after:A)early film newsreels and shortsB)vaudevilleC)radioD)the newspaper3.Until 1956, television programming was always broadcast live from New York or filmed in California. By 1960 most programs had switched to tape. What company developed the videotape?A)DuMont B)Ampex C)UHF D)VHF4.In the __________, television underwent a period now referred to as the golden age of television,with much growth and experimentation including programs such as Ed Sullivan's Toast of the Town, Gunsmoke, and Milton Berle's Texaco Star Theater.A)1950s B)1930s C)1940s D)1920s5.What decade is known for its growing public concern with regard to television programming and its effects?A)1950s B)1980s C)1960s D)1970s6.In the 1960s, network news was praised for its coverage for what events?A)the Civil Rights movementB)the Watergate ScandalC)Women's RightsD)all of these7.Which of the following statements in not true about the VCR?A)it encouraged time shiftingB)it allows the viewer to zap or zip by commercialsC)it allowed viewers to record and view content whenever they chose to do soD)it went virtually ignored by the American public8.Much happened in the 1990s involving television. What did not?A)The Telecommunications Act of 1996B)direct broadcast by satelliteC)the sharp increase in popularity of cable networksD)TiV o reaching 90 percent of the population9.All of the following is true about contemporary broadcast television except:A)audiences continue to growB)advertising dollars are going to the webC)broadcasters are relying more on reality shows and less on scripted showsD)the Big Four broadcast networks have moved to newer distribution channels10.Digital television (DTV) has many advantages including:A)fuzzier pictures, more white noise, and a triangular pictureB)clearer pictures, improved sound, and ability for several simultaneous programs from a single channelC)a more rectangular format and high definition (HDTV) capabilitiesD)none of these11.Big networks are using broadband to offer special-interest content that wouldn't be successful on their broadcast channels.A)True B)False12.PBS, the Public Broadcasting Service, is a form of commercial television.A)True B)False13.When a local station signs a contract to be part of a network, the station becomes an affiliate of that network.A)True B)False14.Stations get programming from three types of sources. Which of the following isn't one of themA)local productionB)cable networksC)network programs。

商务英语综合教程(上册)Unit 16 Welcome to the Wired World

Unit 16 Welcome to the Wired World
Text Exercises Related Technical Terms Grammar
Unit 16 Welcome to the Wired World
Text
1 1997 may be the year for the world to catch up with a
vision of a networked future, and the results are shaking up enterprises, economies and governments around the world. Financial markets have moved off paper and onto ether waves; businesses are grabbing at newly globalized markets; and even slow-moving bureaucracies are fingering the Internet, searching for a balance between information and freedom. Starting this week in Davos, Switzerland, 1,200 of the world’s most influential businessmen and politicians---leaders who may not have known a data link from a cuff link a decade ago---will spend six days debating the shape and texture of life in the networked future. An additional journalist, dignitaries and other interested observers will be in attendance.

有关通讯的英语作文

Communication is an essential aspect of human interaction,allowing individuals to share ideas,emotions,and information.In the modern world,various forms of communication have evolved,each with its unique advantages and challenges.The Importance of Effective CommunicationEffective communication is crucial for building and maintaining relationships,whether personal or professional.It helps in resolving conflicts,fostering understanding,and promoting collaboration.Good communication skills involve not only the ability to articulate thoughts clearly but also to listen actively and empathetically.Verbal CommunicationVerbal communication includes facetoface conversations,telephone calls,and video conferencing.It allows for immediate feedback and the conveyance of tone and emotion, which can be crucial for understanding the full context of a message.However,verbal communication can be hindered by factors such as accents,dialects,and cultural differences.NonVerbal CommunicationNonverbal communication encompasses body language,facial expressions,gestures,and eye contact.It can convey messages without the need for words and is often considered more trustworthy as it is harder to manipulate.However,misinterpretations can occur if the sender and receiver are not familiar with each others nonverbal cues.Written CommunicationWritten communication,such as emails,letters,and reports,provides a permanent record of the message.It allows for careful consideration of the content before sending and can be referred back to at a later time.However,it lacks the immediacy of verbal communication and can be prone to misinterpretation without the context provided by tone and body language.Digital CommunicationWith the advent of technology,digital communication has become increasingly prevalent. Social media,instant messaging,and email are all forms of digital communication that offer convenience and speed.They enable communication across vast distances and can be used asynchronously,allowing individuals to respond at their own pace.However,digital communication can also lead to issues such as information overload,the spread of misinformation,and a lack of personal connection.Cultural Considerations in CommunicationCultural differences can significantly impact communication.What is considered polite or direct in one culture may be seen as rude or indirect in another.Understanding and respecting these differences is vital for effective crosscultural communication.Overcoming Communication BarriersTo overcome communication barriers,it is essential to develop skills such as active listening,clarity in expression,and empathy.Additionally,being aware of ones own communication style and adapting it to suit different audiences can greatly improve the effectiveness of communication.The Future of CommunicationAs technology continues to advance,the future of communication is likely to involve even more digital and virtual interactions.Virtual reality and augmented reality may offer new ways to communicate,providing immersive experiences that go beyond traditional methods.In conclusion,communication is a multifaceted process that requires attention to both the content of the message and the method of delivery.By understanding and adapting to the various forms and challenges of communication,individuals can enhance their ability to connect and collaborate effectively in our increasingly interconnected world.。

教师资格之中学英语学科知识与教学能力题库检测试卷A卷附答案

2023年教师资格之中学英语学科知识与教学能力题库检测试卷A卷附答案单选题（共100题）1、Every student as well as teachers who __________to visit the museumasked to be at the school gate on time.A.is; isB.are; areC.is; areD.are; is【答案】 D2、We have no trust in him because he has never__________ the grandiose promises he makes.A.delivered onB.eaten offC.forgotten aboutD.abided by【答案】 A3、/s/and/θ/can be distinguished by__________.A.manner of articulationB.place of articulationC.vibration of the vocal cordsD.aspiration of articulation【答案】 B4、I arrived at the airport so late that I __________missed the plane.A.onlyB.quiteC.narrowlyD.seldom【答案】 C5、/t/is not fully pronounced inA.footballB.suitcaseC.at homeD.hot day【答案】 C6、Which of the following describes the process in which one’s language ability is developed in natural and everyday situation?A.PerformancepetenceC.LearningD.Acquisition【答案】 D7、There are two kinds of motive for engaging in any activity: internal and instrumental. If a scientist conducts research because she wants to discover important facts about the world, that's an internal motive, since discovering facts is inherently related to the activity of research. If she conducts research because she wants to achieve scholarly renown, that's an instrumental motive, since the relation between fame and research is not so inherent. Often, people have both for doing things. What mix of motives--internal or instrumental or both--is most conducive to success? You might suppose that a scientist motivated by a desire to discover facts and by a desire to achieve renown will do better work than a scientist motivated by just one of those desires. Surely two motives are better than one. But as we and our colleagues argue in a paper newly published in the Proceedings of the National Academy of Sciences, instrumental motives are not always an asset and can actually be counterproductive to success. We analyzed data drawn from 11320 cadets in nine entering classes at the United States Military Academy at West Point, all of whom rated how much each of a set of motives influenced their decision to attend the academy. The motives included things like a desire to get a good job later in life and a desire to be trained as a leader in the United States ArmyA.In-service soldiersitary researchersitary officersitary trainees【答案】 D8、Passage 2A.live in very hot temperaturesB.live in very cold temperaturesC.manufacture oxygenD.all of the above【答案】 D9、Passage 1A.mice' s inborn terror of catsB.the evolution of ToxoplasmaC.a new study about the effects of a parasite on miceD.a harmful parasite called Toxoplasma gondii【答案】 C10、Advertisers tend to think big and perhaps this is why they're always coming in for criticism．A.AdvertisementB.The benefits of advertisementC.Advertisers perform a useful service to communitiesD.The costs of advertisement【答案】 C11、Which of the following is based on the communicative view of language?A.Structural syllabusB.Skill-based syllabusC.Genre-based syllabusD.Functional-notional syllabus【答案】 D12、请阅读短文，完成此题。

汽车专业英语读译教程 (梁桂航第3版 ) 习题与答案TEXT B

汽车专业英语读译教程(第3版)TEXT B课后练习题(EXERCISES)参考答案UNIT 1 AUTOMOTIVE BASICSTEXT B Automobile's History/ ・ Translate the following English names of car makers into Chinese:1.General Motors Corporation 通用汽车公司2.Ford Motor Co.福特汽车公司3.Chrysler Motors Corporation 克莱斯勒汽车公司4.Toyota Motor Corporation 丰田汽车公司5.Nissan Motor Co. Ltd.日产汽车公司6.Honda Motor Co. Ltd.本田汽车公司7.Mitsubishi Motors Corporation 三菱汽车公司8.Mercedes-Benz AG梅赛德斯-奔驰汽车公司9.BMW AG宝马汽车公司10.Volkswagen AG群众汽车公司11.Audi AG奥迪汽车公司12.Suzuki Motor Corporation 铃木汽车公司13.Isuzu Motors Ltd.五十铃汽车公司14.Mazda Motor Corporation 马自达汽车公司15.Volvo Car Corporation 沃尔沃轿车公司16.Volvo Bus Corporation 沃尔沃巴士公司17.Porsche AG保时捷汽车公司//. Translate the following English names of cars into Chinese:1.Chevrolet Corvette; Buick Century; Cadillac Deville 雪佛兰克尔维特；别克世纪；凯迪拉克德维尔2.Ford Mustang; Ford Mendeo; Lincoln Town Car 福特野马；福特蒙迪欧；林肯城市3.Dodge Caravan; Jeep Grand Cherokee; New Yorker 道奇捷龙；吉普大切诺基；纽约人ndcruiser; Camry; Crown; Lexus陆地巡洋舰；凯美瑞；皇冠；雷克萨斯1.What are the advantages of continuously variable transmission?Because there are no gears to tie a given road speed directly to a given engine speed, the CVT can vary the engine speed as needed to access maximum power as well as maximum fuel efficiency. This allows the CVT to provide quicker acceleration than a conventional automatic or manual transmission while delivering superior fuel economy.2.What are the main components of automated manual transmission?Transmission control ECU, clutch activator, transmission actuator, operators, and sensorsII. Translate the following paragraph into Chinese ：The basic technical criteria for continuously variable transmissions are size, weight, transmission-ratio range, transfer efficiency, noise emissions and installation possibilities. With regard to these aspects, mechanical continuously variable transmissions, in the form of chain-driven transmission, have provided the best results so far.评判无级变速器的基本技术标准是尺寸、重量、传动比范围、传动效率、噪声排放和安装可能性。

2022年考研考博-考博英语-西南财经大学考试全真模拟易错、难点剖析AB卷(带答案)试题号：72

2022年考研考博-考博英语-西南财经大学考试全真模拟易错、难点剖析AB卷（带答案）一.综合题(共15题)1.单选题This river is so wide that it is impossible to build a （）under it without modern technology.问题1选项A.canalB.tunnelC.channelD.cable【答案】B【解析】考查名词词义辨析。

canal “运河，管道”；tunnel “隧道”；channel “通道，海峡”；cable “缆绳，电缆”。

句意：这条河这么宽，要在它地下修建一条隧道没有现代技术是不可能实现的。

选项B 符合题意。

2.单选题Parks and open spaces are essential to the quality of life in dense （）areas such as New York City.问题1选项A.agriculturalB.ruralC.suburbanD.urban【答案】D【解析】形容词辨析题。

agricultural农业的；rural乡村的；suburban郊区的；.urban城市的。

句意：公园和空地对于像纽约这样人口密集的城市地区的生活质量来说是必不可少的。

选项D符合语境。

3.单选题The journalist got the （）news that the famous actress would change her husband for the seventh time.问题1选项A.sentimentalB.sensationalC.sensibleD.sensitive【答案】B【解析】考查形容词辨析。

sentimental意为“伤感的，多情的，多愁善感的”；sensational意为“轰动的，引起哗然的”；sensible意为“明智的，理智的，合理的”；sensitive意为“敏感的，易受伤害的”。

中南大学2008年博士研究生入学考试英语试题的复习资料解析

中南大学2008 年博士研究生入学考试英语试题参考答案与解析Paper OnePart I Using of EnglishSection One Vocabulary and Structure1【答案】A【解析】从题目中neither side 可以看出，是两方在讨论，所以应该是one side and the other side。

本句采用了岛状结构，起强调作用。

强调“双方在争论中没有达成协议”，因为双方都不愿让步。

所以正确答案是A 选项2【答案】D【解析】四个选项的意思分别是lightest 最轻的；furthest，最远的；smallest，最小的；faintest，模糊的。

the faintest idea 意思是，一点概念没有。

句意是，我对你的意思一点也不明白，你能再讲清楚点么？所以正确答案是 D 选项，如We haven't the faintest idea what the murderer looks like.（这个杀人犯长得怎么样我们连一点概念也没有。

）3【答案】A【解析】语法题。

it's no good doing something 的意思是，做某事无济于事。

这里的good 还可以替换成use，it 可以替换成there。

据此，可以推出正确答案是A 选项。

句意是，我还不知道什么时候可以去度假，现在做决定没有意义。

It’s no如good crying now!（现在哭也没用了！。

）4【答案】B【解析】四个选项的意思分别是give away 赠送，泄漏；give off 发出（光，声音等），散发出（气味）；give in 认输，投降；give up 停止，放弃。

句意是加装了防护过滤器以后，这烟囱已不再散发成股的废气到大气中去了。

根据句子意思推出正确答案是B 选项，如As motor vehicles burn fuel, they give off carbon monoxide as a waste.（汽车燃烧燃料时，会产生废气—一氧化碳。

Communication in the Presence of Noise

Communication in the Presence of Noise CLAUDE E.SHANNON,MEMBER,IREClassic PaperA method is developed for representing any communicationsystem geometrically.Messages and the corresponding signals arepoints in two“function spaces,”and the modulation process is amapping of one space into the ing this representation,anumber of results in communication theory are deduced concern-ing expansion and compression of bandwidth and the thresholdeffect.Formulas are found for the maximum rate of transmissionof binary digits over a system when the signal is perturbed byvarious types of noise.Some of the properties of“ideal”systemswhich transmit at this maximum rate are discussed.The equivalentnumber of binary digits per second for certain information sourcesis calculated.I.I NTRODUCTIONA general communications system is shown schemati-cally in Fig.1.It consists essentially ofﬁve elements.1)An Information Source:The source selects one mes-sage from a set of possible messages to be transmitted tothe receiving terminal.The message may be of varioustypes;for example,a sequence of letters or numbers,asin telegraphy or teletype,or a continuous function of timeA precise meaning will be given later to the requirement of reliable resolution ofthe in cps starting at zero frequency,and that we are allowed to use this channel for a certain period oftime,and whose time functions liewithin theinterval,and to have the time functionvery small outside theintervalcontains no frequencieshigherthansecondsapart.This is a fact which is common knowledge in the communication art.The intuitive justiﬁcation is that,if,it cannot change toa substantially new value in a time less than one-half cycle of the highest frequency,that is,1/2.Then.If welet(5)O n t h e l e f t a r e t h e v a l u e s o ft h c o e f ﬁc i e n t i n a F o u r i e r -s e r i e s e x p a n s i o n o f t h e f u n c t i ona s a f u n d a m e n t a lp e r i o d .T h i s m e a n s t h a t t h e v a l u e s o f t h e s a m p l e s .T h u s t h e y d e t e r m i n e,a n d f o r l o w e r f r e q u e n c i e sd e t e r m i n e s t h e o r i g i n a l f u n c t i o nc o m p l e t e l y .T h e r e i s o n e a nd o n l y o nef u n c t i o n w h o s e s p e c t r u m i s l i m i t e d t o a b a n ds e c o n d sa p a r t .T h e f u n c t i o n c a nb e s i m p l y r ec o n s t r u s a m p l e s b y u s i n g a p u l s e o f t h e t y p es ina n d z e r o at ,i .e .,a t a l l o t h e r s a m p l e p o i n t s .F u r t h e r m o r e ,c o n s t a n t i n t h e b a ndt h s a m p l e .T h e n t h e f u n c t i ond oe s n o t s t a r ta t z e r o f r e q u e n c yb u t a t s o m e h i g h e r v a l u e ,p r o v e d b y a l i n e a r t r a n s l a t i o n (c o r r e s p o nd i n s i n g le -s i d e b a n d m o d u l a t i o n )of t h e z e r o -f r e q t h i s c a s e t h e e l e m e n t a r y p u l s e i s o b t a i n e d f ra n d t h es a m p l e s a r e s p a c e d 1/2i f ,a n d o n l y i f ,a l l t h e s a m p l e s o u t s i d e t h i s i n t e r v a l a r e e x a c w e c a n s a y t h a t a n y f u n c t i o n l i m i t e d t o t h ebn u m b e r s .T h e o r e m 1h a s b e e n g i v e n p r e v i o u s l y i n o t b y m a t h e m a t i c i a n s 3b u t i n s p i t e o f i t s e v i d e n t i m p o r s e e m s n o t t o h a v e a p p e a r e d e x p l i c i t l y i n t ho f c o m m u n i c a t i o n t h e o r y .N y q u i s t ,4,5h o w e v e r ,a n d m o r er e c e n t l y G a b o r ,6h a v e p o i n t e d o u t t h a t a p p r o x i m a t e l.T h i s g i v e n a nd.T h e s l i g h t d i s c r e p a n c y i s d u e t o tt h a t t h e f u n c t i o n s o b t a i n e d i n t h i s w a y w i l l n l i m i t e d t o t h e b a nds e c o n d s i n c o n n e c t i o n w i t h t e l e g r a p h y ,a n d wt h e N y q u i s t i n t e r v a l c o r r e s p o n d i n g t o t h e b aTheindependent numbers associated with thefunction can be used to describe it.III.G EOMETRICAL R EPRESENTATION OF THE S IGNALSA set of threenumbers,,,regardless of their source,can always be thought of as coordinates of a point in three-dimensional space.Similarly,thedimensions.Each particularselection of these numbers corresponds to a particular point in this space.Thus there is exactly one point corresponding to each signal in thebandwill be,in general,veryhigh.A 5-Mc television signal lasting for an hour would be represented by a point in a spacewithdimensions.Needless to say,such a space cannotbe visualized.It is possible,however,to study analytically the propertiesof]by a simple entity (a point)in acomplex environment((8)whereisthesin(12)where.Similarly,the distance between two pointsis,these will correspond to points within a sphere ofradius(13)If noise is added to the signal in transmission,it means that the point corresponding to the signal has been moved a certain distance in the space proportional to the rms value of the noise.Thus noise produces a small region of uncertainty about each point in the space.A ﬁxed distortion in the channel corresponds to a warping of the space,so that each point is moved,but in a deﬁnite ﬁxed way.In ordinary three-dimensional space it is possible to set up many different coordinate systems.This is also possible in the signal spaceofcan be expanded as a sum of sines andcosines offrequenciesdimensions with theset of possible signals.In a similar way one can associate a space with the set of possible messages.Suppose we are considering a speech system and that the messages consistSHANNON:COMMUNICATION IN THE PRESENCE OF NOISE449Fig.2.Reduction of dimensionality through equivalence classes.of all possible sounds which contain no frequencies over a certainlimit;thatis,the total amplitude for this frequency.The reduction infrequency discrimination of the ear as frequency increasesindicates that a further reduction in dimensionality occurs.The vocoder makes use to a considerable extent of theseequivalences among speech sounds,in theﬁrst place byeliminating,to a large degree,phase information,and inthe second place by lumping groups of frequencies together,particularly at the higher frequencies.In other types of communication there may not be anyequivalence classes of this type.Theﬁnal destination issensitive to any change in the message within the fullmessage spaceoflimited to theband,which will,of course,be less than or equalto450Table1Fig.3.Mapping similar to frequency modulation.number of dimensions.Single-sideband amplitude modula-tion is an example of this type and an especially simple one,since the coordinates in the signal space are proportional to the corresponding coordinates in the message space.In double-sideband transmission the signal space has twice the number of coordinates,but they occur in pairs with equal values.If there were only one dimension in the message space and two in the signal space,it would correspond to mapping a line onto a square so that thepointof the messagespace may be lessthandimension in the signal space for a goodmapping.To make this saving it is necessary,of course,to isolate the effective coordinates in the message space,and to send these only.The reduced bandwidth transmission of speech by the vocoder is a case of this kind.The question arises,however,as to whether further reduction is possible.In our geometrical analogy,is it possible to map a space of high dimensionality onto one of lower dimensionality?The answer is that it is possible,with certain reservations.For example,the points of a square can be described by their two coordinates which could be written in decimalnotation(14)From these two numbers we can construct one number by taking digits alternatelyfrom(15)A knowledgeofdetermines determinesboth .Thus there is a one-to-one correspondence between the points of a square and the points of a line.SHANNON:COMMUNICATION IN THE PRESENCE OF NOISE451This type of mapping,due to the mathematician Cantor,can easily be extended as far as we wish in the direction of reducing dimensionality.A spaceofThere is a sense in which thisstatement is true,and another sense in which it is false.It is not possible to map the message space into the signal space in a one-to-one,continuous manner (this is known mathematically as a topological mapping)unless the two spaces have the same dimensionality;i.e.,unless.Hence,if we limit the transmitter and receiverto continuous one-to-one operations,there is a lower bound to theproduct in the channel.This lower bound is determined,not by theproduct of message bandwidth and time,but by the number of essentialdimension,and thatit is added to the transmitted signal to produce the received signal.A white thermal noise has the property that each sample is perturbed independently of all the others,and the distribution of each amplitude is Gaussian with standarddeviation is the average noise power.How many different signals can be distinguished at the receiving point in spite of the perturbations due to noise?A crude estimate can be obtained as follows.If the signal has apower.The number of amplitudes that can be reasonably well distinguishedisis a small constant in the neighborhood ofunity depending on how the phrase “reasonably well”is interpreted.If we require very goodseparation,to be larger.Since intime independent amplitudes,the total number of reasonably distinct signalsislogbe the average transmitter power,andsuppose the noise is white thermal noise ofpower.By sufﬁciently complicated encoding systems itis possible to transmit binary digits at aratelogwith as small a frequency of errors as desired.It is not possible by any encoding method to send at a higher rate and have an arbitrarily low frequency of errors.This shows that theratebut reduceerrors by using more involved encoding and longer delays at the transmitter and receiver.The transmitter will take long sequences of binary digits and represent this entire sequence by a particular signal function of long duration.The delay is required because the transmitter must wait for the full sequence before the signal is determined.Similarly,the receiver must wait for the full signal function before decoding into binary digits.We now prove Theorem 2.In the geometrical represen-tation each signal point is surrounded by a small region of uncertainty due to noise.With white thermal noise,the perturbations of the different samples (or coordinates)are all Gaussian and independent.Thus the probability of a perturbation havingcoordinates (these are the differences between the original and received signal coordinates)is the product of the individual probabilities for the differentcoordinatestimes the averagenoise power during thetimeincreases,thisaverage noise power mustapproach,the perturbation will almost certainly be to some point near the surface of a sphere ofradiussufﬁciently large we can insure (with probability as near to one as we wish)that the perturbation will lie within a sphere ofradiuswhere is very large.The received signals have an averagepower,and in the same sense must almost all lie onthe surface of a sphere ofradius-dimensionalsphere 8ofradiusof distinguishablesignalsislogwhenbinary digits is taken in at the trans-mitter.Thereare .Thus thereare different signal functions.When the sequenceofpossible transmitted signals and selects the one which is nearest the perturbed signal (in the sense of rms error)as the one actually sent.The receiver then constructs,as its output,the corresponding sequence of binary digits.There will be,therefore,an overall delayof seconds.To insure a frequency of errors lessthan signal functions must be reasonably well separated from each other.In fact,we must choose them in such a way that,when a perturbed signal is received,the nearest signal point (in the geometrical representation)is,with probability greaterthan ,the actual original signal.It turns out,rather surprisingly,that it is possible to chooseourdifferent samples of band-limited white noise withpowerpoints in the sphere corre-sponds to a particular encoding system.The general scheme of the proof is to consider all such selections,and to show that the frequency of errors averaged over all the particular selections is lessthanFig.5.The geometry involved in Theorem2.particular selections in the set with frequency of errors lessthan,receivedsignalis the regionof possible signals that might havecausedis of smallervolume than a sphere ofradiusby equating the area of thetriangle,calculated twodifferentways)lyinginsignal points.Hence theprobabilityareoutside(24)When these points areoutsidegreaterthan,thefrequency of errors will be lessthanispositive.Consequently,(25)will be trueif(27)orloglog,we can satisfy this bytakinglog.We can also send at therate.This completes the proof.VIII.D ISCUSSIONWe will call a system that transmits without errors at theratelogthe number of bitsper cycle of band vertical.The circles represent PCMsystems of the binary,ternary,etc.,types,using positiveand negative pulses and adjusted to give one error inaboutparison of PCM and PPM with ideal performance.three,etc.,discrete positions for the pulse.9The difference between the series of points and the ideal curve corresponds to the gain that could be obtained by more involved coding systems.It amounts to about 8dB in power over most of the practical range.The series of points and circles is about the best that can be done without delay.Whether it is worth while to use more complex types of modulation to obtain some of this possible saving is,of course,a question of relative costs and valuations.Thequantitylog ,the number of bits that can be transmitted intime,can be altered at will without changing the amount of information we can transmit,providedlog,the noisepowerwherelog ,i.e.,and is known as Gaussiannoise.We can calculate the capacity of a channel perturbed by any Gaussian noise from the white-noise result.Suppose our total transmitter poweris(32)since,for each elementary band,the white-noise result applies.The maximum rate of transmission will be found bymaximizinglog(34)or.For frequencieswhere the noise power is low,the signal power should be high,and vice versa,as we would expect.The situation is shown graphically in Fig.8.The curve is the assumed noise spectrum,and the three lines correspond to different choicesof is small,we cannotmakeFig.8.Best distribution of transmitter power.zero at other frequencies.With low valuesofin the band.X.T HE C HANNEL C APACITY WITH AN A RBITRARY T YPE OF N OISEOf course,there are many kinds of noise which are not Gaussian;for example,impulse noise,or white noise that has passed through a nonlinear device.If the signal is perturbed by one of these types of noise,there will still be a deﬁnite channelcapacity(35)be the probability that these amplitudes liebetweenand ,etc.Then thefunction successive samples are concerned.Theentropy(37)This limit exists in all cases of practical interest,and can be determined in many ofthem.,the entropyisexp(39)whereacts very much like a whitenoise ofpowerhavepoweris thenboundedbyis the average signal powerandlogapproaches the upper limit.XI.D ISCRETE S OURCES OF I NFORMATIONUp to now we have been chieﬂy concerned with the channel.Thecapacityletter is often followedbyis the probability of the sequence of symbols,and the sum is over all sequencesof(43)It turns outthatmessage symbols into sequences of binary digits in such a way that the average number of binary digits per message symbol is approximately anda discrete source ofentropy,,,,and successive letters are chosen independently,thenlogand the information produced is equivalent to 1.294bits for each letter of the message.A channel with a capacity of 100bits per second could transmit with bestencodingmessage letters per second.XII.C ONTINUOUS S OURCESIf the source is producing a continuous function of time,then without further data we must ascribe it an inﬁnite rate of generating information.In fact,merely to specify exactly one quantity which has a continuous range of possibilities requires an inﬁnite number of binary digits.We cannot send continuous information exactly over a channel of ﬁnite capacity.Fortunately,we do not need to send continuous messages exactly.A certain amount of discrepancy between the orig-inal and the recovered messages can always be tolerated.If a certain tolerance is allowed,then a deﬁnite ﬁnite rate in binary digits per second can be assigned to a continuous source.It must be remembered that this rate depends on the nature and magnitude of the allowed error between original and ﬁnal messages.The rate may be described as the rate of generating information relative to the criterion of ﬁdelity .Suppose the criterion of ﬁdelity is the rms discrepancy between the original and recovered signals,and that we can tolerate avalue,entropypower of generating information in bits per second is boundedby(44)whereanda source whose rate of generatinginformation,it is possible to encode the source insuch a way as to transmit over this channel with the ﬁdelitymeasuredby,this is impossible.In the case where the message source is producing white thermalnoise,.Hence the two bounds are equaland .We can,therefore,transmit white noise ofpowerperturbed by a white noise ofpower(45)A PPENDIXConsider the possible sequencesofth message is encodedbyexpandinglog(46)Probable sequences have short codes and improbable ones long codes.Wehave(48)or(49)The average number of binary digits used per message symbolis,.SHANNON:COMMUNICATION IN THE PRESENCE OF NOISE457Authorized licensed use limited to: IEEE Xplore. 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高考英语缩略词与缩写识别高级判断练习题题20题答案解析版

高考英语缩略词与缩写识别高级判断完形填空题20题答案解析版1**题干**：In today's digital age, technology is advancing at an astonishing pace. AI (Artificial Intelligence) has become an integral part of our lives. From smart phones to self-driving cars, AI is everywhere. Another important technology is VR (Virtual Reality), which offers immersive experiences. Scientists are also working on developing new materials. For example, graphene is a wonder material with extraordinary properties. The development of 5G networks is also crucial for the future of communication. It will enable faster data transfer and more reliable connections.**Question 1**: AI stands for ————.A. Actual IntelligenceB. Artificial InsanityC. Artificial IntelligenceD. Advanced Information答案：C。

AI 是Artificial Intelligence 的缩写，这是常见的科技缩略词。

A 选项Actual Intelligence 实际智力，与AI 的常见释义不符；B 选项Artificial Insanity 人工疯狂，不符合通常的表述；D 选项Advanced Information 高级信息，也不是AI 的正确释义。

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The ultimate capacity of a communication network is essentially quantum-limited, and the main concern of quantum communication is how to discriminate among quantum states that encode the relevant information [1]. Quantum coding states are generally nonorthogonal, such that they cannot be unambiguously discriminated. As a consequence, the detection strategy should be optimized at the receiving side, in order to maximize the detection probability and/or minimize the transmission errors. The scheme we have in mind is the following: a binary alphabet A = {0, 1} with equal a priori probability symbols is being transmitted through a quantum communication channel. The information is encoded in two arbitrary Gaussian quantum states ̺0 and ̺1 . In the following we ﬁrst consider the case of pure states |ψ0 and |ψ1 , whereas, in the second part of this letter, the analysis will be extended to the mixed-state case. Information is amplitude-keyed encoded [2], such that the wave functions of the two states are given by 1 x2 ψ0 (x) = x|ψ0 = √ exp − 2 + if0 (x) 2σ 2πσ 2 (x − a)2 1 exp − ψ1 (x) = x|ψ1 = √ + if1 (x) , (1) 2σ 2 2πσ 2 where fj (x), j = 1, 2 are arbitrary phases, and a ∈ R+ . Since the two states have the same a priori probability of being transmitted, the mean total energy traveling through the channel is given by ET = a2 /2 + (σ 2 − 1/2)2 /σ 2 (measured in unit of hτ , τ being the characteristic time of the physical channel, e.g. the period for a bounded system, or the time-length of the wave-packet for a free system). The case σ 2 = 1/2 corresponds to customary on-oﬀ coherent modulation, whereas for σ 2 < 1/2 we are dealing with squeezed states [3]. Although squeezing increases the total energy introduced into the channel, we will show that it can be eﬀectively employed to
Nearly ideal binary communication in squeezed channels
Matteo G. A. Paris
Quantum Optics & Information Group, Istituto Nazionale per la Fisica della Materia Universit` a di Pavia, via Bassi 6, I-27100 Pavia, Italy (February 1, 2008) We analyze the eﬀect of squeezing the channel in binary communication based on Gaussian states. We show that for coding on pure states, squeezing increases the detection probability at ﬁxed size of the strategy, actually saturating the optimal bound already for moderate signal energy. Using Neyman-Pearson lemma for fuzzy hypothesis testing we are able to analyze also the case of mixed states, and to ﬁnd the optimal amount of squeezing that can be eﬀectively employed. It results that optimally squeezed channels are robust against signal-mixing, and largely improve the strategy power by comparison with coherent ones.
an inconclusive inference in order to achieve error-free discrimination [5]. Actually, these have been fruitful approaches in quantum state recognition, especially in the M -ary decision problem [6]. However, the price of a small error probability is usually a small detection probability too, which, in turn, may imply the requirement of a high repetition rate. On the other hand, in the ﬁeld of communication there exist several protocols that are robust [7], i.e. that may satisfactorily work also with a nonzero transmission-error rate. In this case, the main interest is that of maximizing the detection probability Q1 , while maintaining the size Q0 to a moderated tolerable level. A decision strategy which is optimized according to such a criterion, which we will employ throughout this letter, is said to be a Neyman-Pearson (NP) optimized strategy [8].
At the receiver, we consider the standard detection of the signal observable X , µ ˆ(x) = |x x|, such that the output probability densities are given by p0 (x) = | x|ψ0 |2 = G(x; 0, σ ) and p1 (x; a) = | x|ψ1 |2 = G(x; a, σ ), where G(x; a, σ ) = (2πσ 2 )−1/2 exp[−(x − a)2 /2σ 2 ] is a normalized Gaussian of mean a and variance σ 2 . On the basis of each measurement outcome we have to discriminate between two hypothesis: the null hypothesis H0 corresponding to the transmission of |ψ0 (no signal), and the alternative hypothesis H1 , corresponding to the transmission of |ψ1 , i. e. to the presence of the signal. The process of measurement and inference is called a decision strategy. We denote by Q1 the power of the strategy, that is the probability of inferring the alternative hypothesis when the signal is actually present (also called the detection probability), and by Q0 the size of the strategy, i. e. the probability of inferring the alternative hypothesis when the null hypothesis is true (also called the falsealarm probability). In the following we employ a threshold strategy, in which the alternative hypothesis is chosen if the outcome is greater than a threshold value x0 . In order to determine the threshold value we should optimize the strategy, a goal that, in turn, requires to adopt an optimization criterion. Usually, one uses the criterion of minimizing the average cost of the decision, that is, in Bayesian terms, that of minimizing the probability of a wrong inference [4]. Alternatively, one may accept to occasionally obtain 1