Teleportation and Dense Coding with Genuine Multipartite Entanglement

对我生活影响巨大的科技英语作文Tech That's Changed My LifeHi! My name is Sam and I'm 10 years old. I love technology and it has really changed my life in so many ways. Today I want to tell you about some of the amazing tech that has had a huge impact on me.First up is something I couldn't live without - my smartphone!I got my first smartphone when I was 8 years old and it has been my best friend ever since. I use it for everything - playing games, watching videos, taking photos and videos, messaging my friends and family, and even doing my homework sometimes.My favorite game is Roblox. I can spend hours creating my own worlds and games on there. I've made so many friends from all over the world by playing and chatting with them on Roblox. We team up, explore different games, and just have a ton of fun together. Sometimes we even video chat while playing so it feels like we're in the same room! Roblox has also helped me learn about game design which is something I'd love to do as a job when I'm older.Instagram and TikTok are two other apps I'm obsessed with.I follow so many cool creators and influencers who makeamazing videos and take incredible photos. It inspires me to work on my photography and video skills. I've even started my own channels where I post pictures of my daily life, my pets, and fun videos I make with my friends. I have a few thousand followers already which is really exciting! Who knows, maybe I'll be an influencer myself one day.Speaking of photos and videos, the cameras on modern smartphones are just mind-blowing. I can take pictures and videos that look like they were shot on a professional camera. The portrait mode makes me look like a model and the slo-mo videos are hilarious. My friends and I are constantly snapping shots and recording silly videos to share with each other. It's the best way to capture fun memories.My smartphone also lets me learn new things in ways that are way more engaging than just reading books or listening to teachers. There are so many great educational apps, videos, podcasts, and even AR experiences. One of my favorites is a science app that uses augmented reality to teach me about things like the solar system, the human body, and all sorts of other topics. I can see 3D models appear in my room and interact with them. So cool!Another education tech I love is language learning apps. I'm trying to learn Spanish and French at the moment. The apps make it almost like a game with fun lessons, stories, and even speech recognition to help me practice pronunciation. I use them for just 20-30 minutes a day but I'm already picking up the languages way faster than I would through normal classes. Who knows how many languages I'll speak when I'm older thanks to apps like these?While smartphones are probably the technology that has impacted me the most, they aren't the only amazing modern tech in my life. At home, we have smart speakers like Alexa and Google Home that let us control everything by just using our voice. I can get them to play my favorite music, set timers and reminders, answer random questions I have, and even tell jokes. It's like having my own personal assistant!We also have robot vacuum cleaners that automatically clean the floors in our house every day while we're at school. No more coming home to a messy house! And smart lights that turn on automatically when someone enters a room. Not to mention all the cool smart home gadgets that help us monitor energy usage, control the temperature, and secure our home.Some of my other favorite tech includes wireless headphones that let me listen to endless music and podcasts without getting tangled in cords, drones I can fly around and get a bird's eye view, and even 3D pens that let me create 3D designs and sculptures by just drawing in the air. The possibilities seem endless!In school, tech is also a huge part of how we learn nowadays. We each have tablets or laptops for doing work, taking notes, watching educational videos, and even video calling experts and other classes. Our textbooks are all digital now too which is way easier than lugging around heavy books. And we have interactive whiteboards in every classroom that can pull up any information or resource we need.Technology definitely has its downsides too though. I've learned a lot about online privacy, cyberbullying, and the importance of taking breaks from screens. There's also the environmental impact of all the devices and the unethical ways some tech companies operate. My parents and teachers are always reminding me to be a responsible digital citizen.Still, despite the potential negatives, I really do feel incredibly lucky to be growing up in this time of rapid technological progress. The innovations we have access to todaywould seem like pure magic and science fiction to people just a couple of decades ago. I can't even imagine what newmind-blowing tech will be invented by the time I'm an adult!Who knows, maybe I'll be one of the brilliant minds helping to create the next era of transformative technologies. An AI coding assistant to help programmers at a thought?Hyper-realistic virtual worlds to explore? Or even teleportation devices to travel across the globe in an instant? The possibilities are endless thanks to tech progress.For now though, I'm just going to keep having fun with all the awesome gadgets and apps at my fingertips. I'll use them to learn, create, connect with others, and get a head start on exploring my many interests. Modern tech may be incredible, but I'm probably one of the luckiest kids around to get to grow up surrounded by it. It really has changed my life in so many ways, and I can't wait to see what future innovations have in store!。

专利名称：System and method for transferring data packets through a communication systemwith ring topology to a multimedia deviceutilizing a different communication protocol 发明人：Hetzel, Herbert,Knapp, David J.申请号：EP05011315.8申请日：20050525公开号：EP1603284B1公开日：20121121专利内容由知识产权出版社提供摘要：A communication system, network, interface, and port architecture are provided for transporting different types of data across a network. The network can be arranged by connecting the ports in a daisy chain fashion to achieve a ring architecture or topology. The network forwards data according to a specific network protocol, and any incoming data that follows that protocol will be sent onto the network. If the incoming data protocol does not match the network protocol, then the incoming data is not sent immediately to the network, but instead is sent to an input pin of a device upon the network specifically designed to receive that incoming data. The network, therefore, has ports that support both compliant and non-compliant incoming data, and the devices that produce such data. Examples of non-compliant data include any data which does not time-division multiplex different asynchronous, isochronous, and synchronous data in dedicated channels within each frame, and which have a preamble, coding, frequency, or overall protocol different from that which is established for network transfer.申请人：STANDARD MICROSYST SMC地址：US国籍：US代理机构：Lohr, Georg 更多信息请下载全文后查看。

生活中的科技展览高考英语作文Technology is Everywhere!Hi there! My name is Tommy and I'm 10 years old. Today I want to tell you all about the cool technology exhibits I've seen lately. Technology is so awesome and it's all around us - even more than most people realize. Whether it's the smartphone my mom uses, the tablets we have for school, or the robots you see on TV shows, technology impacts our lives in so many ways.Just last weekend, my family went to a huge technology expo at the convention center downtown. I was so excited because I love anything related to science and computers. The minute we walked in the door, I was blown away by all the amazing exhibits and displays. It was like stepping into the future!The first thing that caught my eye was this gigantic robot arm. It had to be at least 20 feet tall! The robot could pick up cars and heavy objects like they were nothing. The guy working the exhibit let me control the robot arm for a minute using a video game controller. It was so rad! I made the arm pick up a big boulder and then put it back down. I would love to have one of those robot arms to help me clean my room.Next up, we checked out some virtual reality headsets. By putting on the headset, you could be transported to amazing 3D worlds and play games unlike anything I've ever experienced. One second I was in outer space flying through asteroid fields, and the next I was underwater exploring a vibrant coral reef. The graphics looked incredibly real. My parents had to pull me away because I didn't want to take the headset off!Another super awesome part of the expo had to do with 3D printing. You could design any kind of 3D object on the computer, and then these printers would physically create the object layer by layer out of plastic. It was like magic! I made a 3D printed model of my dog Buddy and they let me take it home. I can't wait to show my friends.While checking out the computer section, I also got to program a small robot to move around and follow commands. It was like playing with a super advanced video game system, but one where I got to actually create the character's behaviors. I'm already dreaming up ideas for my own robot video game.My favorite part of the whole expo, though, had to be the drone obstacle course. Companies make these small quadcopter drones that you can fly around using your smartphone. The obstacle course let you pilot a drone through rings, aroundpillars, and under tunnels - kind of like a video game level in real life. I was terrible at it at first and crashed the drone like a million times. But eventually I got better and even won a small prize at the end! Drones are just so cool.Seeing all this incredible technology gave me a million ideas for inventions I want to create when I grow up. How awesome would it be to have a hoverbike that you could fly to school instead of taking the bus? Or a pair of smart glasses that display hologram screens in front of your eyes? Or even a real-life lightsaber? A kid can dream...Another big focus was technology to help the environment. They had displays of electric cars, better renewable energy sources like wind and solar, and ways to reduce waste through more efficient product designs. I even got to plant a tiny tree sapling using a robot arm! I know protecting the planet is crucially important, so it's awesome that technology is being used to help solve problems like pollution and climate change.Seeing all these incredible technology exhibits has me more excited than ever about the future. Just imagining where computers, robotics, biotech, and other fields will be in 20 or 30 years blows my mind. The technology we'll have access to will be unbelievable compared to today.I definitely want to be an inventor or engineer when I grow up so I can work on creating the next big technological breakthroughs. I'm already tinkering with electronics kits and teaching myself coding. The world needs more scientific minds finding new ways to use technology to explore new frontiers and help make people's lives better.Thinking about how much amazing technological progress has happened already in my short 10 years of life, I can't even fathom how advanced things will be by the time I'm an adult. Maybe we'll finally have those flying cars and jet packs I've dreamed about. Or teleportation devices to beam yourself across the world. Heck, we might even find a way for humans to live on Mars or other planets! How crazy is that?While there's no telling exactly what mind-blowing technologies the future will bring, one thing is certain - science and innovation will keep pushing the boundaries of what's possible. And I can't wait to be a part of it. The world of tomorrow is going to be one wild, crazy, hyper-advanced ride. Just call me Tommy, future tech wizard!Well, that's all I've got for now. Thanks for reading, and make sure to stay tuned for the next big thing coming out of SiliconValley. The best is yet to come! Okay, time for me to go design my own video game...。

1.PCM原理抽样量化与编码:sampling,quantizing and coding话路:speech channel幅值: amplitude value抽样频率: sampling frequency抽样速率: sampling rate脉冲流: stream of pulses重复率: repetition rate编码过程: coding process模拟信号: analog signal传输质量: transmission quality数字通信: digital communication数字传输: digital transmission含噪声的环境: noisy environment传输路由: transmission path信噪比 :signal-to-noise ratio信号电平 :signal levels噪声功率: noise power地面系统: terrestrial system二进制传输: binary transmission反向操作: reverse operation8-位码序列: 8-digit sequence接受端: receiving terminal帧格式 :frame format同步字 :synchronization word实现这三项功能的方案 :the schemes for performing these three functions一串幅值: a series of amplitude values电话质量的话路 a speech channel of telephone quality一个8位二进制码的序列: a sequence of 8-binary digits理论上的最小抽样频率 :a minimum theoretical sampling frequency占据着300Hz到3.4kHz频率范围的话路: a voice channel occupying the range 300Hz to 3.4kHz 每个样值8-位码: 8-digits per sample value汽车点火系统的打火: the sparking of a car ignition system重复率为64kHz的脉冲流: the stream of the pulses with a repetition rate of 64kHz真实信号与噪声信号的关系: relationship of the true signal to the noise signal由卫星上接受到的信号 :the signal received from a satellite一条特定消息中的全部信息 :the complete informatian about a particular message被传信号的波形 :the shape of the transmitted signal由传输路由引入的衰减: the attenuation introduced by transmission path将抽样的幅值转换成一串脉冲的单元 :the unit that converts sampled amplitude value to a set of pulses涉及到第一路，第二路及其他各路的序列: a sequence relating to channel 1,2 and so on被称为同步字的独特码序列: a unique sequence of pulses called synchronization word地面系统 :terrestrial system脉冲的“有”或“无” : the presence or absence of the pulses高速的电子开关: a high-speed electronic switch时分多路复用器 :the time division multiplexer时分多路复用 :Time Division Multiplexer2.异步串行数据传输串行接口 serial interface显示终端 CRT terminal发送器与接收器 transmitter and receiver数据传输 data transmission数据流 data stream闲置状态 the idle state传号电平 mark level空号电位 space level起始位 start bit停止位 stop bitT秒的持续时间 duration of T seconds奇偶校检位 parity bit错误标志 error flag传输错误 transmission error下降沿 fallinf edge符号间的空格 intersymbol space接收机的定时 receiver timing本地时钟 local clock磁带 magnetic tape控制比特 control bit逻辑1电平 logical 1 level二进制数据 binary data明显的缺点 obvious disadvantage异步串行数据传输 asynchronous serial data transmission最为流行的串行接口 the most popular serial interface所传送的数据 the transmitted data发送器与接收器的时钟 the clocks at the transmitter and receiver电传机的时代 the era of teleprinter一个字符的点和划 the dots and dashs of a character符号间空格持续时间的三倍 three times the duration of intersymbol space被称为字符的比特组 the group of bits called characters由7或8个比特的信息组成的固定单元 the invariable units comprising 7 or 8 bits of information 由接收机本地产生的时钟 a clock generated locally by the receiver在字符后所收到的奇偶校检位 the received parity bit following the character起始位的下降沿 the falling edge of the start bit数据链路面向字符的特性 the character-oriented nature of the data link3.数据通信地下电缆 underground cable通信卫星 communication satellite微波设备 microwave facilities调制器与解调器 modulator and demodulator缓冲器 buffer定时信号 timing signals同步脉冲 synchronization pulses时隙 time slot移位寄存器 shift register传输媒体 transmission medium线形衰弱 linear attenuation信息安全 information security键盘 keyboard数据终端 data terminals某种类型的数据转换设备 some type of data conversion equipment视频显示终端 visual display terminal称为数据调制解调器的双向数据发送接收机 two-way data transmistter-receiver called a data modem 全双工的数据传输系统 full-duplex data trandmission system由数据处理器的运算速率所决定的速率 the rate determined by the operating speed of the data processor由接口部件来的定时信号 timing signals from the interface assembly磁心存储器 magnetic core memories线性衰减和时延特性 linear attenuation and delay characteristics传输损伤 transmission impairments语音中的冗余特性 the redundant nature of speech在数据发送器中的编码过程 coding process in the data transmitter二进制的不归零信号 binary nonreturn-to-zero signal4.互联网网络资源：network resource信息服务：information services远程终端：remote terminals互联的系统：interconnected systems命令：command电子邮件：electronic mail主机：host无线信道：wireless channels搜索工具：searching tools用户界面：user interface存取：access文本信息：textual messages协议：protocol超文本协议：hypertext protocol分布在全世界的计算机的巨大网络：gaint network of computers located all over the world主干系统：backbone system全国范围的网络：nationwild network电子会议：electronic conferences实时对话：live conversation最大的信息库the largest repository of the computers on the net网络设备资源：network facilities resources在网上的绝大多数计算机：the vast majority of the computer on the netUNIX操作系统：the UNIX operating system在因特网和你的PC机之间传送数据的方法：a way to move data between the internet and your PC 方便的搜索工具：the convenient searching tools联网的超文本协议：the network hypertext protocol5.光纤通信介绍光纤通信:optical fiber communications光源：light source波长：wavelength激光器：laser色散：dispersion传输介质：transmission medium多模光纤：multi-mode fiber长途干线：long-houl trunks单模光纤：singer-mode fiber带宽：bandwidth带宽用户：wideband subscriber纤维光学：fiber-optics商用技术：commercial technologe门限电流：threshod current光检测器：photodetector波分复用：wavelength multiplexing纤维光网络：fiber-optic network视频带宽：video bandwidth长途传输：long distance transmission中继距离：repeater spacing已装光纤的总长度：the total length of installed fiber长途通信系统：long-haul telecommunication system低衰减的石英纤维：the low-loss silica fiber衰减接近瑞利极限的光纤：fibers with losses approaching the Rayleigh limit室温下的门限电流：room temperature threshold currents较长波长区：the longer wavelength region用户接入工程：subscriber access project部件性能和可靠性的改进：improvements in component performance and reliability已安装的光纤系统的数据速率：data rates for installed fibre optic system每秒吉比特：gigabit per second range波分复用：wavelength multiplexing带宽用户环路系统：widebend subscriber loop system多纤连接器：multifibre connectors设计寿命：projected lifetime光源：light source单模光纤：single-mode fibre分布反馈式激光器：distributed-feedback laser信息容量：information capacity交换体系：switching hierarchy带宽业务：broadband services9.蜂窝式移动电话系统蜂窝式移动电话：cellular mobile telephone服务性能：services performance频谱：frequency spectrum频带：frequency band微处理器：microprocessor移动手机：mobile unit广播业务：broadcast servise天线：antenna子系统：subsystems移动用户：mobile subscriber服务能力：service capability利用率：utilization带宽：bandwidth单边带：single-sideband扩频：spread spectrum大规模集成电路：large scale integrated circuits蜂窝点：cellular site蜂窝交换机：cellular switch无线机架：radio cabinet呼叫处理：call processing频谱利用率：frequency spectrum utilization有限的指定频带：the limited assigend ferquency band 服务区：servise area复杂的特性和功能：complicated features and functions大规模集成电路技术：large-scale integraesd circuit technology试验性的蜂窝系统：developmental cellular system中央协调单元：central coordinating element蜂窝管理：cellular administration传统移动电话的运行限制：operational limitiation of conventional mobile telephone system 有限的服务能力：limitied service capability无线通信行业：radio communcation industry可用的无线电频谱：available radio frequency spectrum所分配的频带：the allocated frequency band移动收发信机：mobile transceiver技术上的可行性：techological feasibility严格的频谱限制：severe spectrum limitations调频广播业务：FM broadcasting services传播路径衰耗：propagration path loss多径衰耗：multipath fading电话公司地方局:telephone company zone offices10.全球移动通信系统个人通信 personal communcation通信标准 communcation standrads固定电话业务 fixed telephone services网络容量 network capability移动交换中心 mobile switching center国际漫游 international roaming宽带业务 broadband services接口转换 interface conversion频谱分配 frequency allocation模拟方式 analogue mode蜂窝通信原理 cellular communcation principe拥塞 jamming蜂窝裂变 cellular splitting基站 base station寄存器 register收费功能 billing function接入方法 access method突发脉冲传输方式 brusty transimission mode开销信息 overhead information切换算法 handover algorithms短消息服务 short message services技术规范 technical specificationtotal access communcation system 全接入的通信系统global mobile communcation system 全球移动通信系统time division multiple access 时分多址facsimile and short message services 传真和短消息服务fixed communcation networks 固定通信网络a more personalized system 更加个性化的系统the cost and quality of the link 链路的价格和质量market growth 市场的发展fixed telephone service 固定电话服务coxial cable 同轴电缆interface convision 接口转换cellular communcation priciple 蜂窝通信原则frequency reuse and cell splitting 频率复用和蜂窝裂变cochannel interference 共信道干扰theoretical spectual capability 理论上的频谱容量micro-cellular system 微蜂窝系统base station transceiver 基站收发信机subscriber register 用户寄存器burst transmission mode 突发脉冲传输模式overhead information 开销信息advanced handover algorithms 先进的切换算法facsimile and short message services 传真和短消息服务the GSM technique specications GSM技术规范说明一1 . 研究二进制的传输可见, 只要简单地去判别脉冲的“有”和“无”, 我们就获得了一条消息的全部信息。

科技产物影响我的生活,英语作文Technology and My LifeHi there! My name is Sam and I'm 10 years old. I love technology - it's such a big part of my life! Today I'm going to tell you all about the different gadgets and gizmos that make my world go round.Let's start with something I use every single day - my tablet! My parents got me a kid-friendly tablet for my 8th birthday and I don't know what I'd do without it. I use it for games, videos, browsing fun websites, and even some schoolwork. My favorite game is an adventure game where I get to explore different worlds and complete quests. The graphics are so cool and realistic. I also watch a lot of science videos on there - I'm really interested in space exploration and black holes and stuff. My tablet lets me learn about those topics in a fun, interactive way with awesome video clips and animations.My tablet also connects to the internet, which lets me video chat with my grandparents who live far away. We have "virtual sleepovers" every other weekend where I can show them my latest art project or comic book, and they can read me bedtime stories. The video quality is so good that it feels like they're rightthere in the room with me. Technology is great for keeping families connected across long distances.Speaking of the internet, that's another major way technology impacts my life. I use it for research for my school projects and reports. Just this week, I had to write a paper on Ancient Egypt, so I googled facts about the pharaohs, the pyramids, mummies, hieroglyphics and more. I found awesome pictures, videos, and articles that really brought my report to life. The internet is like having every library in the world at your fingertips!My family also relies a lot on tech for entertainment. We have a giant smart TV that lets us stream movies, shows, music, and games with just a voice command or the push of a button. My favorite is when we have movie nights - we order pizza, dim the lights, and rent the latest kid-friendly flick right there on the TV. The picture is crystal clear, with colors that pop off the screen. And the sound system shakes the room when there's an explosion or earthquake on screen. It's an awesome experience that makes you feel like you're part of the movie!Another really cool piece of tech I use is my smart speaker. It's this little device I can talk to and ask questions, and a friendly robot assistant answers me. I'll ask it things like math questionswhen I'm doing homework, how to spell words I'm not sure of, or random facts about animals or planets. I can even get it to tell jokes and play games with me. My smart speaker makes studying a lot more fun and interactive. I can also use it to set reminders for myself, like when I have a big test coming up or a dentist appointment.Video games are another way technology entertains me and helps pass the time. I have a handheld gaming device that lets me play all the newest games. The graphics are mind-blowing - so detailed and lifelike. And the gameplay is super immersive with amazing sound effects and music that changes based on what's happening in the game. Some games now even let me put on a virtual reality headset and it feels like I'm literally inside the game world. How crazy is that?!Of course, I do have to be careful not to spend too much time on all these devices. My parents set screen time limits and make sure I take breaks to go play outside, read physical books, or do other activities. It's all about balance. But tech is just so fun and engaging that sometimes I have a hard time unplugging!I'm also really interested in coding and programming - creating technology, not just using it. My school actually teaches coding classes, which I love. We use kid-friendly codingprograms to build our own basic apps, games and websites. I got to make a simple spaceship shooter game last semester that my whole family played. Coding shows me the magic happening behind the scenes to make tech work. It feels like harnessing a superpower! I may want to create the next big app or video game when I grow up.Technology isn't just for fun though - it's an important tool for learning in the classroom as well. My teacher has an interactive whiteboard that she can use to play educational videos, look up definitions or diagrams, or work through problems with us. Way more engaging than a boring old chalkboard! We even have a 3D printer that lets us design and print our own models and creations. I printed a miniature rocket ship last year that I'm really proud of.Some technology is also making the world a better place. My dad has an electric car that doesn't pollute the environment like gasoline-powered cars. And we have solar panels on our roof that generate clean electricity just from the sun's rays. More and more buildings are being constructed using eco-friendly materials and design too. Scientists and inventors are always coming up with amazing new technologies to help protect the planet.In the future, I expect technology will keep advancing and changing at lightning speed. Maybe we'll have flying cars, seamless virtual reality environments, or even teleportation devices. Just think - with a few taps, you could go anywhere in the world in an instant. How awesome would that be? Or maybe I'll become a brilliant inventor myself and create the nextmust-have technology everyone goes crazy for. The possibilities are endless and exciting!As you can probably tell, I'm a total tech-obsessed kid. Technology shapes my education, entertainment, communication and so much more on a daily basis. It opens up amazing new worlds for me to explore right from my own home. While some might say kids my age are glued to screens too much these days, for me technology is a bridge that sparks curiosity, learning, and creativity. It brings the magic of the universe into my life with just a tap or swipe. Technology is pretty neat if you ask me!。

创建一个俱乐部招募广告英语作文全文共5篇示例，供读者参考篇1Hi friends! Do you like having fun? Do you like doing cool stuff with your friends? Then you should totally join my new club that I'm starting!I'm calling it the "Awesome Activities Club" and it's gonna be the best club ever. We're going to do all kinds of awesome activities and have tons of fun. Let me tell you all about it!First of all, every week we're going to have a meeting where we decide what totally awesome activity we want to do that weekend. It could be anything - going to the park, having a picnic, playing games, doing a craft project, you name it! Whatever we all vote for is what we'll do. Majority rules!And the activities aren't just gonna be boring ol' regular stuff either. We're going to make them as fun and silly and crazy as possible! Like, if we decide to go to the park one week, it won't just be going to the park. No way! We'll turn it into an adventure and pretend we're explorers trekking through the jungle. Wecould make binoculars out of toilet paper rolls to look for exotic animals and stuff. How cool would that be?!Or if we decide to do a craft project, we won't just make anything boring like a yechchh pottery cup or something. We'll make epic stuff like superhero costumes and masks! Or awesome gadgets and inventions out of popsicle sticks and pipe cleaners. You could finally have that teleportation device you've always wanted!And that's just a couple of ideas. I have a billion more where those came from. My brain is like a fun idea factory that never stops! We could do treasure hunts, carnival games, build forts and play battlefield like we're in an army platoon, put on crazy plays and concerts, endless possibilities! Whatever we can come up with, that's what we'll do in the club.The best part is, you don't even have to be "good" at anything to be in this club. You don't have to be good at sports or arts and crafts or anything. You just have to be willing to use your imagination and be a little silly and goofy and have an open mind for trying new things. That's all you need to have fun in the Awesome Activities Club!We'll meet up every Friday afternoon right after school gets out. My parents said we can use the recreation room in ourapartment building for the meetings. It's a huge room with tables and chairs and a kitchen area, so it'll be perfect for whatever we want to do. My parents will be around too just to keep a basic eye on things, but they promised to give us our space and freedom to run everything ourselves.So what do you think? Are you interested in joining my club? It's going to be so epically awesome! Just imagine, every weekend you'll get to do some kind of hilarious, ridiculous, incredibly fun activity instead of sitting around being bored at home. Who wouldn't want to sign up for that?The only catch is, we're going to have to limit the amount of members, at least at first. See, if we have too many people, it'll be way too hard to get anything done or make decisions. So for now, we're going to cap it at 10 members total. That's it! Just 10 lucky people will get to be in my super cool club initially.Don't worry though, if you don't make it in this first round, we'll definitely open it up to more people soon if it goes well. And I'll probably make everyone re-apply or something anyway just to make sure the club has a good mix of personalities. You don't want a club where everyone is exactly the same!Ooh, I just got another idea too - we could break the club up into smaller "units" and have unit leaders and competitionsbetween units sometimes. Like a unit obstacle course challenge! How sweet would that be?! You guys are going to love this club, I can already tell.Anyway, I've rambled on enough. If you're interested in being one of the first 10 members of the Awesome Activities Club, just let me know! You can come talk to me at school, call me, email me, send me a letter by carrier pigeon, whatever! Just get a hold of me and let me know you want in.To join, you just have to tell me your name, grade, and favorite kind of animal. Oh, and also what you're interested in or what kind of activities you'd love to do in the club. That'll help me make sure we get a nice variety of interests and ideas going on.For example, if it was me joining, I'd say:"Hi, I'm Timmy, I'm in 4th grade, and my favorite animal is a tiger. I really like doing arts and crafts, playing games, and putting on plays and skits and stuff."Something like that! Make sure to include all those key details when you tell me you want to join. Then cross your fingers and hope you make the cut for those first 10 awesome spots!I'll be deciding the first group of members in about two weeks. So round up your friends who'd be interested and get your submissions in fast before all the spots are filled up!Once we get the club started, we're gonna have a blast. I can't wait! This is gonna be the funnest, silliest, most awesome club ever. Just you wait and see!Okay, that's all for now. Start getting those applications in, my friends! I'll be waiting to assemble the most epic Awesome Activities Crew around. This is gonna be legendary!篇2Welcome, Friends! Are You Looking for Fun?Hi everyone! My name is Jamie and I am a 5th grader here at Oakwood Elementary. I love trying new things and having fun adventures with my friends. That's why I've decided to start my very own club called the "Explorers Club!"In the Explorers Club, we will get to go on exciting trips around our town and discover all the cool places and activities we never knew existed before. We'll visit museums, parks, restaurants, you name it! Every week will be a new surprise journey.But the Explorers Club isn't just about going places. We'll also get to try out different hobbies and games. One week we might learn how to juggle. Another week we could put on a magic show. We'll never do the same thing twice!I'm looking for a crew of curious, adventurous kids to join me. You have to be willing to step out of your comfort zone and embrace new experiences. An Explorer is brave, open-minded, and eager to have fun!If this sounds awesome to you, then you're exactly the type of person I want in my club. But spaces will be limited, so you'll need to act fast. Here are the key details:Who: Students in grades 3-5What: The Explorers Club - exploring our town through exciting field trips and activitiesWhen: Meetings every Saturday from 10am - 2pm, starting April 22ndWhere: We'll meet at a different location each week based on the trip/activity plannedCost: 25 per month to cover admission fees, supplies, etc.To secure your spot, you'll need to bring a few key things to our first meeting on April 22nd:Completed registration form (attached) with parent's approvalYour first month's payment of 25A spirit for adventure!At our first meeting, we'll vote on exploring ideas for the rest of the year, create our club t-shirts, and much more. Snacks will be provided!Don't miss your chance to have an unforgettable year filled with friends, thrills, and new experiences. Sign up for the Explorers Club today! Let's go on some excellent explorations together.Your Explorer-in-Chief,JamieP.S. Still need to convince your parents? Remind them that the Explorers Club will help you step out of the screen/gaming world and into the real world. You'll get exercise, tap into your creativity, and absorb tons of cultures and knowledge. What could be better?篇3Come One, Come All! Join the Coolest New Club!Hi everyone! My name is Jamie and I'm a 5th grader at Oakwood Elementary. I have a really exciting idea that I want to tell you all about. Are you bored after school with nothing to do? Well, so was I, until I had the awesome idea to start...a CLUB! That's right, an actual club that we kids can be in charge of. How cool is that?!This isn't going to be just any boring old club though. This is going to be the BEST club that ever existed at our school. It's going to be a club all about having fun, being creative, and getting to do all the awesome activities and games that we can never do during regular class time. No more sitting at desks or taking notes - this is pure awesomeness!So what kind of club is it going to be exactly? Well, I was thinking it could be a cool mix of all the things us kids love most. We can have arts and crafts, outdoor adventures, video games, cooking activities, science experiments, and more! Anything we can imagine, we can make it happen in our club. The best part is, we get to make all the decisions ourselves on what we want todo each week. No teachers bossing us around - just pure kid power!Here are some of the mega cool ideas I've had so far for club activities:Arts and CraftsPainting and drawing contests with prizesMake our own custom t-shirts, hats, or other merchSculpting with clay, playdough, papier mâchéJewelry making with beads and cool materialsOrigami challengesVideo Game TournamentsSmash Bros, Mario Kart, Overwatch, you name it!Bring your favorite multiplayer gamesHave Lincoln and Spring tournamentsWin prizes and bragging rightsOutdoor AdventuresHiking and nature walks in nearby parksBuild outdoor forts and structuresHave scavenger hunts and exploreLearn survival skills like camping, firebuildingScience AwesomenessMake volcanos and gooey slimeSimple coding and programming activitiesCatapult and rocket building competitionsHands-on experiments like crystal growingExplore electricity, magnets, and moreCooking CreationsBake yummy treats like cookies and cupcakesHave pizza making or sushi rolling contestsLearn about nutrition and healthy snacksInvent and name our own unique food creationsAnd those are just a few of my million dollar ideas! I'm sure once we all put our heads together, we'll come up with enough amazingly fun activities to keep us busy for months. The greatest thing is, whatever we decided to do for that week's club meeting,it will be something we all want to do and voted on together. No more lame school approved stuff - this is 100% kid-approved!Now, you're probably wondering - how can we actually start this too-good-to-be-true club? Well, here's what I was thinking. We'll need to:Find a cool teacher or parent who can be our club supervisor. Don't worry, they'll just be there to make sure we're being safe and following rules. We kids will be the real leaders calling all the shots.Get a group of at least 8-10 kids to be the founding members. That way we'll have enough people to get the club going strong right from the start!Decide on a day, time, and place to have our club meetings. Maybe an evening after school two days a week? Or a weekend morning? We'll pick a time that works for everyone.Make a list of reasons why our club should officially exist and present it to Mr. Bailey, the principal. We'll explain how it will be educational, fun, and productive!Spread the word and keep recruiting more members once our club is approved. The more kids we have, the more skills and ideas everyone can bring to make it even better.Decide how we'll fund the club. We may need to collect small monthly dues from members to pay for supplies and materials. Or do some fundraising activities.So what do you all think? Does a club like this sound like the awesome-est thing ever or what? Imagine a place where we can kick back, relax, and just have tons of fun with our friends after school. No boring homework or classes to worry about. Just gaming, crafting, snacking, and making memories that will last forever!If you want to be a part of this incredible club from the very beginning, talk to your parents and let them know you're interested. Then come find me on the playground or after school and give me your name. I'll add you to my list of kids who are 100% in for the funnest club of all time!Once we get everything set up and officially approved, we'll have an epic first meeting to decide on a cool name for our club. We'll also vote on club member positions like President, Vice President, Treasurer, and other roles. We'll make our own rules, designs, secrets handshakes - maybe even official merch! The possibilities are endless when we use our creativity.What are you waiting for? This is your chance to be a part of something awesome! No more boredom after school - justextraordinary fun and adventure with your friends. So raise your hand if you're ready to be a founding member of the greatest club to ever exist! This is just the beginning, but together we can make it huge. Let's go篇4Hi everyone! My name is Amy and I'm a 4th grader at Oakwood Elementary School. I have a super exciting idea that I want to tell you all about. Are you ready? I want to start a brand new club just for kids like us! It's going to be called the "Friends of Furry Critters" club. How awesome does that sound?You might be wondering, what exactly is the "Friends of Furry Critters" club? Well, let me explain! Basically, it's going to be a club where we get together after school and learn all about cute, cuddly animals like puppies, kittens, bunnies, hamsters, and more. We'll learn what they like to eat, where they live, how to properly take care of them, and all that good stuff.But that's not all! The really fun part is that we're actually going to get visits from some special furry guests. You read that right - real live animals are going to come hang out with us at our club meetings! Can you imagine getting to pet an adorablepuppy or snuggle a soft bunny? It's going to be the best thing ever.And here's the most exciting news of all...at the end of the year, the school is going to let each member of the club ADOPT a pet of their very own! Isn't that insanely cool? I'm already dreaming about the cute little kitty or hamster I might get to take home. We'll have to be really responsible pet owners though, so we'll learn everything we need to know to give our new furry friends the best care.Sounds amazing, right? I knew you'd be just as psyched about this idea as I am! The club will meet once a week after school on Thursdays from 3:00pm to 4:30pm. We'll have so much fun learning about animals, playing games, making crafts, and of course, getting up close and personal with all our special furry visitors.There's just one teeny tiny catch...we need at least 10 members to officially start the club. That's where you come in! I need all my fellow animal lovers to join with me. If you can't get enough of cuddly critters and would love the chance to hang out with them after school, then this club is definitely for you.Talk to your parents and see if they'll let you join. Membership is only 5 for the whole year - that's a steal of a dealfor all the cuteness we'll experience! Just bring the 5 fee to Mrs. Johnson in the front office along with a permission slip signed by your mom or dad.Hurry though, because space will be limited! Once we get our first 10 members, the club will be closed for membership. You don't want to miss out on this opportunity to shower some love on all the furry friends this world has to offer. Who knows, you might even get to take a brand new pet home at the end!I'll be waiting anxiously to see who joins. If we get enough members, our first club meeting will be on Thursday, September 12th at 3:00pm in Room 21 (Mrs. Adam's classroom). Mark your calendars, because the fur-tastic fun will begin that day! I can't wait to see you all there.Spread the word with your friends, because the more the merrier when it comes to cuddling cute critters. Just imagine how great it will feel to make a new furry friend's day bygiving them scratches, treats, and plenty of love. They'll be so happy, and you'll be too!So whatdya say, who wants to join the "Friends of Furry Critters" club with me? Let's do this thing! Get your permission slips and 5 fee in quickly so you can reserve your spot. This is going to be the BEST club ever.See you soon, future pet owners and animal experts!Your pal,Amy篇5A New Cool Club for Everyone!Hi friends! My name is Tommy and I'm starting a super awesome new club at our school. I'm so excited to tell you all about it!This club is going to be the funnest club ever. We're going to do all kinds of cool activities and games. You'll never be bored again after school if you join!What kind of club is it? Well, it's a mix of everything fun. We'll play sports sometimes like soccer, basketball, and kickball. Other times we'll do arts and crafts. Maybe we'll paint pictures one day. The next day we could make friendship bracelets or build things out of popsicle sticks and glue.We'll also go on adventures and field trips! How does a trip to the ice cream shop sound? Yum! Or maybe we could have a picnic at the park and fly kites. We'll use our imaginations and goexploring into the woods behind the school too. Who knows what kind of treasures and cool nature things we might find?On rainy days, we could have indoor activities and games. We could put on plays and talent shows. I'm a pretty good magician so I can teach you all some magic tricks too! We could also do science experiments. It will be super fun and you might even learn something.Doesn't this club sound awesome so far? I told you it was going to be the best! But there's more...Sometimes we'll just hang out, listen to music, and chat about our favorite movies, video games, books, and tv shows. We can even have special days where we all dress up as our favorite characters. How cool would it be to have a whole club of Elsas, Spider-Men, and Harry Potters running around?The best part is, YOU get to help decide what we do! At our meetings, everyone can share ideas and we'll all vote on activities. This is our club, so we'll do whatever fun things we all want.I really want this new club to be a place where everyone feels welcome and can make lots of new friends. You don't have to be "cool" or anything like that to join. You just have to be yourself and be ready for fun!There's no limit on how many people can join either. The more the merrier! I want this to be a huge club with tons of members. I'll even let you bring your little brothers and sisters sometimes if you want.Grown-ups like parents and teachers are welcome to help out too if they'd like. But this will be a kid-run club. That means us kids will make all the decisions and rules ourselves. How awesome is that?So what do you think? Are you ready to sign up and be a member of the funnest, coolest, most awesome club ever?! Just tell your teachers or parents that you want to join. I'll set up meetings once a week after school where we can vote on activities and make our plans for epic fun!I can't wait for our first club meeting. We're all going to have so much fun together. We'll play games, go on adventures, make crafts, put on shows, and so much more! This club is going to be legendary. Your days of being bored after school are over, my friends! Let's go have fun!Who's in? Join the Cool Fun Club today!。

实现纠缠交换的基本方案王菊霞【摘要】阐述了量子隐形传态及量子纠缠交换的基本理论，通过单光子的量子纠缠交换、连续变量纠缠交换实证说明纠缠交换的机制，纠缠交换可使得从未直接发生相互作用的量子系统产生纠缠，利用纠缠交换可达到实现信息传递的目的，纠缠交换是目前信息学中实现信息交换非常重要的途径之一。

%The description of quantum teleportation and entanglement swapping theory is given.The mechanism of entanglement swapping is illustrated to make use of demonstration in a single-photon and continuous-variable entanglement swapping.It is an im-portant protocol in quantum information science since it enables to entangle two particles that have never interacted in order to realize information transfer.【期刊名称】《渭南师范学院学报》【年(卷),期】2014(000)023【总页数】4页(P17-20)【关键词】量子信息学;量子隐形传态;纠缠交换;信息传递【作者】王菊霞【作者单位】渭南师范学院物理与电气工程学院; 渭南师范学院陕西省X射线检测与应用研究开发中心，陕西渭南714099【正文语种】中文【中图分类】O4311993年，由Zukowki［1］等人提出纠缠交换的概念.两个从未直接相互作用的量子系统之间要产生相互关联可以通过纠缠交换的过程来实现，更重要的是可以建立远程非局域关联.潘建伟等人［2］则最先利用纠缠交换在实验上制备出光子间的纠缠态;在2004年底由彭堃墀院士的研究团队首次实现了连续变量的纠缠交换这一重要的基础实验［3］;纠缠交换是量子隐形传态的一个特例，其表现形式是纠缠态的量子隐形传送.要实现纠缠交换，必须得理解量子态、量子纠缠等基本概念，特别值得一提的是，量子纠缠是量子信息最基本的源泉，迄今为止，量子纠缠已被广泛应用于量子隐形传态、量子编码、量子保密通讯和量子计算等领域.1997年，《自然》杂志上发表了一篇具有里程碑意义的研究论文《实验量子隐形传态》，该篇文章引起了全球物理界的轰动，被欧洲物理学会、美国物理学会、美国《科学》杂志等大量宣传及高度评价，此后相应的理论研究非常活跃，直到2004年，相关实验“五光子纠缠和终端开放量子隐形传递”由潘建伟研究团队首次实现［4］，这个实验的难度相当大，《自然》杂志称赞此成果是一壮举;随后的研究更上一层楼，取得了一系列重大成果.目前，在光量子纠缠操纵和量子通信方面，我国已经处于领跑的位置.［4］迄今为止，已有多种实现量子纠缠交换的方案［5-12］，本文阐述了纠缠交换的基本理论与实现纠缠交换最基本最典型的实证，通过单光子的量子纠缠交换、连续变量纠缠交换的方案，说明了实现纠缠交换的基本机制，旨在了解比较抽象的“纠缠交换”的实质内容及实际应用.1 量子隐形传态对于两个或两个以上子系统构成的量子体系，在任何量子力学表象中，如果无论如何体系都不可能由组成该体系的各子系统对应的量子态矢用直积形式来表示，那么这些子系统之间就存在一定的关联，即表现出相互纠缠的不可分特性，这种情况下它们即使在空间中分离，当对一个子系统的测量时也必然会影响其他子系统的测量结果，这种相互依存的非定域关联称为量子纠缠，简称纠缠.［5-6］量子隐形传态方案首次由Bennett等六位科学家联合在Phys.Rev.Lett.(1993年)上发表论文《由经典和EPR通道传送未知量子态》中提出［13］，由此引起了人们对这方面的热烈讨论，直到1997年Bouwmeester、潘建伟等人在实验上首次实现.［14］最早提出的量子隐形传态也叫远距隐形传物，当时的远距传物，类似于不少科幻影片中都出现过的场景:一个神秘人物在某处突然消失掉，然后在另一处莫名其妙地显现出来.在经典物理中的解释为:传送一个物体就是传送组成它的全部经典物理特征，那么只要将原物的所有信息能提取出来，传送这些信息的速度只要不超越光速极限，即使传至遥远的地点，然后利用获得的信息重新构制出与被传送对象完全相同的复制品，这种重新组装的物体就可完成经典客体的隐形传物.［15-16］2 纠缠交换的基本理论设发送者Alice(简称A)和接收者Bob(简称B)，他们分别掌握纠缠光束对a，b和c，d，即初始时刻a与b之间存在纠缠，c与d之间存在纠缠，但是，a，b与c，d之间互不纠缠，如果通过第三方Claire(简称C)，对b和c进行联合Bell基测量［17］，由于测量导致的纠缠塌缩，将使得之前没有任何关联的光学摸a和d之间就会产生纠缠，也就是说通过联合测量，这个操作相当于利用c和d之间的EPR纠缠，将量子态b离物传送至d，在模d上再现模b的量子态特性，从而使模d与模a产生纠缠，即可完成纠缠的转移，这一过程称之为纠缠交换(Entanglement Swapping).通常判断纠缠交换是否实现的实验方法有两种:一种是直接测量关联度.初始模a和模d之间无任何关联，如果测量它们之间的关联达到一定程度，则通过纠缠交换产生了量子关联，也就说明纠缠交换得以实现.［18］另一种是利用量子隐形传态实验，将纠缠交换后的模a和模d作为相干光的纠缠光束，进行相应的实验，通过测量量子态的保真度(Fidelity)来作出判断.如果其保真度F＞0.5，则说明a和d之间必然存在纠缠，即完成了纠缠交换.3 单光子的量子纠缠交换一个用于2比特编码单光子控制非门的量子逻辑协议，可实现从动量纠缠转换为偏振纠缠，其实验装置如图1所示，其中使用了参量下转换光子对，它周期性地连接KTP晶体，该晶体属于Ⅱ型共线频率衰减参量下转换产生398.5 nm的连续波.在动量空间中，下转换光束可以分为上半(T)和下半(B)两种模式.图1 单光子纠缠交换方案原理图(PPKTP:周期性连接的KTP晶体;PBS:偏振分束器;HWP:半波片;DP:棱镜;1F:1 nm长的滤光片;D:探测器)根据这些模式动量纠缠态可以写为:其中:H、V分别表示水平和垂直线偏振态.一个交换门可以由三个连续控制非门构成，初始态中的多比特信号光子和闲置光子通过交换门后，由此获得最终偏振纠缠态为:为了实施这个方案需要两种类型的控制非门:偏振控制非门(P-CNOT)和动量控制非门(MCNOT)，在图1中，波片的光轴与水平方向成45°角时光子处于偏振态，光路中放置补偿片是为了抵消两个不同模之间的延迟，此方案中需要能传递两光子的一套控制门.动量模式分离后，M-CNOT的功能可通过用于偏振分析的半波片HWP2来实现，分束器BS两个输出端的探测器将同时记录到光子(即符合计数)，借助于两臂的探测器这种符合计数，可以将两光子投影到Bell基中的单重态上.通过P-CNOT门的偏振态是.图2 符合计数率(θ2=0°时“方点”、θ2=45°时“圆点”)图3 连续变量纠缠交换方案原理图图2表示符合计数度随着偏振分析角θ2变化的情况，其中θ2为臂2中符合计数器与偏振分析仪的夹角，当θ2=0°时用方形点表示，θ2=45°时用圆形点描述，对于0°和45°情形与正弦曲线的符合度分别为(97±2)%和(88±2)%.在这种量子态的传送中，检验正确的平均几率S必须满足一定的数值范围，该实验测量了S值并得到的结果是S=2.653±0.004，突破了经典极限，根据贝尔不等式大于1.50标准偏差，由此证明:从动量纠缠转换为偏振纠缠，即实现了纠缠交换.4 连续变量的纠缠交换连续变量纠缠交换实现的方案如图3所示，由分束器所获的两束光为压缩真空态，它们的结合产生两对相互正交的纠缠对EPR1和EPR2，EPR1由模式1和2构成，而EPR2由模式3和4构成，两者相互独立.纠缠交换的目的是光束1和4之间形成纠缠，可通过模式2隐形传递到模式4＇来实现，而模式4＇与模式1并没有直接相互作用.如果成功实现相关量子传态，那么，模式1和4＇之间将形成纠缠，在这种方法中，纠缠交换的实质是模式2和4＇之间产生纠缠.在连续变量纠缠交换方案中利用了光学参量振荡器(OPO)产生压缩态光束，由860 nm的外腔式倍频蓝宝石激光器分为四个光束为OPO提供泵浦，LO是为探测器提供信号的局域振荡器，AM和PM分别表示振幅调制和相位调制，除了99/1以外的分束器都是50/50，g为经典通道的标准增益.利用不可分离准则验证纠缠交换方案的成功性，模式1和4＇之间的不可分离充分条件为:其中:Xj和Pj(j=1，4')分别是湮灭算符实部和虚部对应的正交相位振幅:即aj=xj+ipj，如果不等式(3)成立，那么，没有直接相互作用的模式1和4＇对应的两个态将会产生纠缠，在实验中，隐形传态的标准化增益g调整到不等式(3)的最小值.在这种情况下，进行了一系列实验测量，〈［Δ(x1-x4')］2〉的增益g ≈ 0.8，测量〈［Δ(x1)］2〉和〈［Δ(x4')］2〉相对于真空态的噪音电平分别是3.56 ± 0.15 dB、3.60± 0.18 dB;进一步测量〈［Δ(x1-x4')］2〉变化量，其结果表明，噪音电平比真空情况降低0.76±0.19 dB.类似的，测量〈［Δ(p1-p4')］2〉的结果是噪音比真空情况降低0.55±0.19 dB.由此得知:不等式(3)的涨落起伏为0.86±0.04.这些结果低于相应的标准量子极限，显然表明模式1和4之间存在非经典关联，则说明成功实现纠缠交换.5 结语纠缠态具有空间非定域关联(noulocalcore-lation)的特性，对于纠缠态的量子体系，即使二者相距遥远且无相互作用，由于对某一子系统的测量过程会导致纠缠的塌缩，从而可以确定另一子系统状态.验证纠缠交换是否真正实现的基本方法是对没有任何相互作用的两个子系统的量子态执行联合关联测量，当它们的正交关联方差均低于相应的标准量子极限时，则说明两个子系统具有量子纠缠特性，即已完成了纠缠交换.正是因为即使是两个遥远的、从来没有直接相互作用的量子体系，纠缠交换能使它们之间产生纠缠，因此纠缠交换将在长距离的量子通讯、量子通讯网络以及未来的量子计算机等领域都有着潜在的、非常重要的应用前景.参考文献:【相关文献】［1］Zukowski M，Zeilinger A，Horne M A，et al.“Even-Ready-Detectors”Bell experiment via entanglement swapping［J］.Phys.Rev.Lett，1993，71(26):4287.［2］Pan J W，Bouwmeester D，Weinfurter H，et al.Experimental entanglementswapping:entangling photons that never interacted［J］.Phys.Rev.Lett，1998，80(18):3891.［3］Jia X J，Su X L，Pan Q，et al.Experimental Demonstration of Unconditional Entanglement Swapping for Continuous Variables［J］.Phys.Rev.Lett，2004，93(25):250501-250504.［4］俞路石，曾皓，潘建伟.量子世界“追梦人”［N］.中国教育报，2014-06-13(1).［5］谢常德，贾晓军，苏晓龙，等.连续变量无条件纠缠交换——纠缠态的量子离物传送［J］.物理，2005，34(8):573-577.［6］彭堃墀.压缩态纠缠与连续变量纠缠交换［J］.激光与光电子学进展，2005，42(12):7-8. ［7］刘红.双光子J-C模型中的纠缠交换方案［J］.甘肃联合大学学报(自然科学版)，2008，22(2):43-44.［8］杨健，任珉，於亚飞，等.利用交叉克尔非线性效应实现纠缠转移［J］.物理学报，2008，57(2):887-891.［9］单传家，夏云杰.外场驱动下腔QED中实现量子纠缠交换的方案［J］.滨州学院学报，2006，22(3):23-27.［10］龚晶，何敏，姚泽清.纠缠交换的量子回路实现［J］.通信技术，2008，41(6):78-80. ［11］栗军.用腔QED技术实现纠缠交换［J］.德州学院学报，2007，23(4):32-34.［12］苏晓龙，潘庆，谢常德.连续变量纠缠交换对系统物理参量的依赖关系［J］.量子光学学报，2004，10(4):157-163.［13］Bennett C H，Brassard G，Crepeau C，et al.Teleporting an unknown quantum state via dual classical and Einstein Podolsky-Rosen Channels［J］.Phys Rev Lett，1993，70(13):1895-1899.［14］Bouwmeester D，Pan J W，Mat tle K，et al.Experimental quantum teleportation ［J］.Nature，1997，390:575-579.［15］郭光灿，郭涛，郑仕标，等.量子信息讲座第六讲量子隐形传态［J］.物理，1999，28(2):120-126.［16］苏晓琴，郭光灿.量子隐形传态［J］.物理学进展，2004，24(3):259-273.［17］Zhang Jing，Peng Kun chi.Quantum teleportation and 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科技影响和改变我们的生活英语作文Technology is Changing Our World!Hi there! My name is Sam, and I'm a 4th grader. Today I want to talk to you about something that is changing our lives in so many ways - technology! From the smartphones our parents use to the computers we have at school, technology is everywhere these days. Some of it is really cool and fun, but some of it can also be challenging too. Let me tell you about the ways I see technology affecting our lives.At SchoolOne of the biggest ways I see technology at work is at my school. Our classrooms have big interactive whiteboards instead of old chalkboards or dry erase boards. The teachers can use these to show us educational videos, display information from the internet, and even have us play learning games or take quizzes right on the board with our fingertips! It makes learning a lot more interactive and engaging.We also have a computer lab at school with desktop computers that each student can use for doing research, typing up assignments and reports, or practicing coding and programming skills. I think learning about computers andtechnology from an early age is really important to prepare us for our future jobs and careers. The world is only going to keep getting more high-tech!At the same time, technology can also be a distraction sometimes. A few of the kids in my class are always trying to sneak looks at their smartphones under their desks when they aren't supposed to. Our teacher has to keep reminding them to put their phones away during lessons. I personally think it's better to give your full focus and attention to learning rather than getting distracted by video games or social media.At HomeTechnology has changed so much about our home lives too.I remember my parents talking about how when they were kids, their families only had one TV, one desktop computer, and no smartphones or tablets at all! Nowadays, everybody in my family has multiple devices like phones, laptops, gaming systems, etc. My parents are always having to set limits on our screen time.That said, I do love being able to use technology for fun and educational activities at home too. My favorite apps let me read e-books, watch videos about science or history topics I'm interested in, play brain games and puzzles, and even code my own basic programs and games. It's like having access to a giantlibrary, video arcade, and toy store all rolled into one at my fingertips!My parents also rely heavily on technology for their jobs. My dad is able to work remotely from home a few days per week by using video conferencing software and connecting to his company's internal networks and databases. And my mom uses her smartphone and tablet constantly to coordinate schedules, communicate with clients, and stay on top of her work emails. I can't even imagine them being able to do their jobs effectively without modern tech tools.In Our CommunitiesTechnology is reshaping our communities and cities too. Self-driving cars might be common by the time I'm old enough to drive! Grocery shopping is shifting a lot to online ordering and delivery services. Restaurants use tablet ordering systems and even have robots helping out in the kitchens. Police use body cameras and high-tech equipment to gather evidence. The list goes on and on.Some of the technology I see in our communities feels like it comes straight out of a sci-fi movie! Like the way packages and food orders get delivered by drones now. Or how you can video call staff at the public library from home and have them showyou where to find a book on their shelves. Or the way buildings use sensors and automation systems to automatically adjust lighting and temperature to save energy.Changes for the FutureLooking ahead, I think technology will keep transforming our lives in unimaginable ways as I get older. Maybe we'll develop teleportation technology and be able beam places instantly? Perhaps we'll have advanced robots that can do our household chores and yardwork for us. Holograms might replace videoconferencing, allowing us to virtual interact as if we're in the same room with someone miles away. Who knows, maybe we'll even finally develop flying cars like in the old science fiction movies!Whatever technological breakthroughs are coming, I'm excited to experience them. At the same time, I hope we are smart about how we use and control technology. We shouldn't let ourselves become too dependent on it or let it make us lazy. And we need to make sure we have rules and safeguards in place so that new technologies don't get misused in unethical or dangerous ways that could hurt people.Overall though, I'm optimistic that the continued advancement of technology will do more good than harm if wemanage it responsibly. It has the potential to cure diseases, reverse environmental damage, reduce poverty and inequality, and solve so many other problems facing the world today. Just as much as technology is changing our daily lives now, it may very well change life on a global scale for future generations.Those are just some of my thoughts on how technology shapes our modern lives and will keep impacting the world moving forward. I may just be a kid, but I can clearly see how this is one of the biggest driving forces creating change all around us. So let's approach the future of technology with a mix of enthusiasm, curiosity, and caution. If we get it right, I think it will keep making our lives easier, more efficient, and flat-out amazing in ways we can't even imagine yet!。

INTERNATIONAL TELECOMMUNICATION UNIONITU-T P.563(05/2004) TELECOMMUNICATIONSTANDARDIZATION SECTOROF ITUSERIES P: TELEPHONE TRANSMISSION QUALITY, TELEPHONE INSTALLATIONS, LOCAL LINE NETWORKSObjective measuring apparatusSingle-ended method for objective speech quality assessment in narrow-band telephony applicationsITU-T Recommendation P.563ITU-T P-SERIES RECOMMENDATIONSTELEPHONE TRANSMISSION QUALITY, TELEPHONE INSTALLATIONS, LOCAL LINE NETWORKSSeries P.10 Vocabulary and effects of transmission parameters on customer opinion of transmissionqualitySubscribers' lines and sets Series P.30P.300 Transmission standards Series P.40Objective measuring apparatus Series P.50P.500 Objective electro-acoustical measurements Series P.60Measurements related to speech loudness Series P.70Methods for objective and subjective assessment of quality Series P.80P.800 Audiovisual quality in multimedia services Series P.900For further details, please refer to the list of ITU-T Recommendations.ITU-T Recommendation P.563Single-ended method for objective speech quality assessmentin narrow-band telephony applicationsSummaryThis Recommendation describes an objective single-ended method for predicting the subjective quality of 3.1 kHz (narrow-band) telephony applications. This Recommendation presents a high-level description of the method and advice on how to use it. An ANSI-C reference implementation, described in Annex A, is provided in separate files and forms an integral part of this Recommendation. A conformance testing procedure is also specified in Annex A to allow a user to validate that an alternative implementation of the model is correct. This ANSI-C reference implementation shall take precedence in case of conflicts between the high-level description as given in this Recommendation and the ANSI-C reference implementation.This Recommendation includes an electronic attachment containing an ANSI-C reference implementation and conformance testing data.SourceITU-T Recommendation P.563 was approved on 14 May 2004 by ITU-T Study Group 12 (2001-2004) under the ITU-T Recommendation A.8 procedure.ITU-T Rec. P.563 (05/2004) iFOREWORDThe International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis.The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics.The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1.In some areas of information technology which fall within ITU-T's purview, the necessary standards are prepared on a collaborative basis with ISO and IEC.NOTEIn this Recommendation, the expression "Administration" is used for conciseness to indicate both a telecommunication administration and a recognized operating agency.Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words "shall" or some other obligatory language such as "must" and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party.INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process.As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database.ITU 2005All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU.ii ITU-T Rec. P.563 (05/2004)CONTENTSPage1 Introduction (1)references (1)2 Normative3 Abbreviations (2)4 Scope (2)5 Convention (5)6 Requirements on speech signals to be assessed (5)7 Overview of P.563 (6)7.1 Vocal tract analysis and unnaturalness of speech (7)7.2 Analysis of strong additional noise (8)7.3 Interruptions, mutes and time clipping (8)classification (8)7.4 Distortion8 Comparison between objective and subjective scores (9)coefficient (10)8.1 Correlation9 High level description of the functional blocks used in P.563 (10)9.1 Description of basic speech descriptors and the signal pre-processing (10)9.2 Description of the functional block 'Vocal tract analysis and UnnaturalVoice' (18)9.3 Description of the functional block 'Additive Noise' (32)9.4 Description of the 'Mutes/Interruptions' functional block components (42)9.5 Description of the Speech Quality Model (46)Annex A – Source code for reference implementation and conformance tests (49)A.1 List of files provided for the ANSI-C reference implementation (49)A.2 List of files provided for conformance validation (50)A.3 Speech files provided for validation with variable delay (57)A.4 Conformance data sets (57)requirements (57)A.5 ConformanceA.6 Conformance test on unknown data (57)Electronic attachment: ANSI-C reference implementation and conformance testing data.ITU-T Rec. P.563 (05/2004) iiiITU-T Recommendation P.563Single-ended method for objective speech quality assessmentin narrow-band telephony applications11 IntroductionThe P.563 algorithm is applicable for speech quality predictions without a separate reference signal. For this reason, this method is recommended for non-intrusive speech quality assessment, live network monitoring and assessment by using unknown speech sources at the far-end side of a telephone connection.Real systems may include background noise, filtering and variable delay, as well as distortions due to channel errors and speech codecs. Up to now, methods for speech quality assessment of such systems, such as ITU-T Rec. P.862, require either a reference signal or they calculate only quality indexes based on a restricted set of parameters like level, noise in speech pauses and echoes.The P.563 approach is the first recommended method for single-ended non-intrusive measurement applications that takes into account the full range of distortions occurring in public switched telephone networks and that is able to predict the speech quality on a perception-based scale MOS-LQO according to ITU-T Rec. P.800.1. This Recommendation is not restricted to end-to-end measurements; it can be used at any arbitrary location in the transmission chain. The calculated score is then comparable to the quality perceived by a human listener, who is listening with a conventional shaped handset at this point.The validation of P.563 included all available experiments from the former P.862 validation process, as well as a number of experiments that specifically tested its performance by using an acoustical interface in a real terminal at the sending side. Furthermore, the P.563 algorithm was tested independently with unknown speech material by third party laboratories under strictly defined requirements.It is recommended that P.563 be used for speech quality assessment in 3.1 kHz (narrow-band) telephony applications only.references2 NormativeThe following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. −ITU-T Recommendation P.48 (1988), Specification for an intermediate reference system. −ITU-T Recommendation P.800 (1996), Methods for subjective determination of transmission quality.−ITU-T Recommendation P.810 (1996), Modulated noise reference unit (MNRU).____________________1This Recommendation includes an electronic attachment containing an ANSI-C reference implementation and conformance testing data.ITU-T Rec. P.563 (05/2004) 1– ITU-T Recommendation P.830 (1996), Subjective performance assessment of telephone-band and wideband digital codecs.– ITU-T Recommendation P.862 (2001), Perceptual evaluation of speech quality (PESQ): An objective method for end-to-end speech quality assessment of narrow-band telephonenetworks and speech codecs.– ITU-T P-series Recommendations – Supplement 23 (1998), ITU-T coded-speech database.3 AbbreviationsThis Recommendation uses the following abbreviations:ACR Absolute Category RatingCELP Code-Excited Linear PredictiondBov dB to overload pointDCME Digital Circuit Multiplication EquipmentERP Ear Reference PointHATS Head and Torso SimulatorIRS Intermediate Reference SystemLPC Linear Prediction CoefficientMOS Mean Opinion ScoreMOS-LQO Mean Opinion Score – Listening Quality ObjectiveMOS-LQS Mean Opinion Score – Listening Quality SubjectivePCM Pulse Code ModulationSNR Signal-to-NoiseRatioSPL Sound Pressure Level4 ScopeBased on the benchmark results presented within Study Group 12 in 2003, an overview of the test factors, coding technologies and applications to which this Recommendation applies is given in Tables 1 to 3. Table 1 presents the relationships of test factors, coding technologies and applications for which this Recommendation has been found to show acceptable accuracy. Table 2 presents a list of conditions for which the Recommendation is known to provide inaccurate predictions or is otherwise not intended to be used. Finally, Table 3 lists factors, technologies and applications for which P.563 has not currently been validated. Although correlations between objective and subjective scores in the benchmark were around 0.89 for both known and unknown data, the P.563 algorithm cannot be used to replace subjective testing but it can be applied for measurements where auditory tests would be too expensive or not applicable at all.It should also be noted that the P.563 algorithm does not provide a comprehensive evaluation of transmission quality. It only measures the effects of one-way speech distortion and noise on speech quality in the same way as it can be investigated by an auditory test assessing listening quality on an ACR scale. The P.563 algorithm scores the speech signal in that way, as it is presented to a human listener by using a conventional shaped handset and listening with a SPL of 79 dB at the ERP.2ITU-T Rec. P.563 (05/2004)Because P.563 models the human quality perception in combination with a common receiving terminal, the degradation produced by a receiving terminal and other equipment in a real monitored connection, which are connected behind the measurement point, cannot be taken into account. Because P.563 predicts listening quality scores, all effects degrading talking quality or conversational quality only cannot be taken into account. That means, the effects of loudness loss, delay, sidetone, talker-echo, and other impairments related to the talking quality or two-way interaction only are not reflected in the P.563 scores. Therefore, it is possible to have high P.563 scores, yet non-optimal quality of the connection overall.It should be highlighted that P.563 is designed for the prediction of speech quality in public switched narrow-band telephone networks. The types and the amount of the distortions, technologies and applications in the validation procedure cover the range of common occurrences in such networks. Extreme situations, even if they fulfil the terms of Table 1, may be predicted inaccurately.Table 1/P.563 – Factors for which P.563 had demonstrated acceptable accuracy andrecommended application scenariosTest factorsCharacteristics of the acoustical environment (reflections, different reverberation times) as used in the validation phase. Mobile and conventional shaped handsets as well as handsfree terminals according toP.340 test-setup in office environments were used (See Note).Environmental noise at the sending sideCharacteristics of the acoustical interface of the sending terminalRemaining electrical and encoding characteristics of the sending terminalSpeech input levels to a codecTransmission channel errorsPacket loss and packet loss concealment with CELP codecsBit rates if a codec has more than one bit-rate modeTranscodingsEffect of varying delay on listening quality in ACR testsShort-term time warping of speech signalLong-term time warping of speech signalTransmission systems including echo cancellers and noise reduction systems under single talk conditions and as they will be scored on an ACR scaleCoding technologiesWaveform codecs, e.g., G.711; G.726; G.727CELP and hybrid codecs ≥4 kbit/s, e.g., G.728, G.729, G.723.1Other codecs: GSM-FR, GSM-HR, GSM-EFR, GSM-AMR, CDMA-EVRC, TDMA-ACELP, TDMA-VSELP, TETRAITU-T Rec. P.563 (05/2004) 3Table 1/P.563 – Factors for which P.563 had demonstrated acceptable accuracy andrecommended application scenariosRecommended application scenarios for P.563Live network monitoring using digital or analogue connection to the networkLive network end-to-end testing using digital or analogue connection to the networkLive network end-to-end testing with unknown speech sources at the far end sideNOTE – For more detailed information, please refer to the published testplans ("Joint Test Plan for Single-Ended Assessment Models", COM 12-D 121, January 2003).Table 2/P.563 –- P.563 is known to provide inaccurate predictions when used in conjunction with these variables, or is otherwise not intended to be used with these variablesTest factorsListening levels, Loudness loss (See Note.)SidetoneEffect of delay in conversational testsTalker echoMusic or network tones as input signalCoding technologiesLPC vocoder technologies at bit rates < 4.0 kbit/s, e.g., IMBE, AMBE, LPC10eApplicationsPredicting talking qualityTwo-way communication performanceNOTE – P.563 assumes a standard listening level of 79 dB SPL and compensates for non-optimum signal levels in the input files. The subjective effect of deviation from optimum listening level is therefore not taken into account.Table 3/P.563 – Factors, technologies and applications for which P.563 has not or not fullybeen validated at the time of the standardizationTest factorsAmplitude clipping of speech (was not included in the evaluation data)Talker dependencies and multiple simultaneous talkersSinging voice and child's voice as input to a codecBit-rate mismatching between an encoder and a decoder if a codec has more than one bit-rate mode Artificial speech signals as input to a codecListener echoEffects/artifacts from isolated echo cancellersEffects/artifacts from isolated noise reduction algorithmsEvaluation of synthetic speech and/or using it as input to a speech codec4ITU-T Rec. P.563 (05/2004)Table 3/P.563 – Factors, technologies and applications for which P.563 has not or not fullybeen validated at the time of the standardizationCoding technologiesCELP and hybrid codecs < 4 kbit/sMPEG-4 HVXCApplicationsMeasurements at the acoustic interface of the receiving terminal/handset, e.g., using HATS5 ConventionSubjective evaluation of telephone networks and speech codecs may be conducted using listening-only or conversational methods of subjective testing. For practical reasons, listening-only tests are the only feasible method of subjective testing during the development of speech codecs, when a real-time implementation of the codec is not available. Also listening-only tests are often not practicable for live network monitoring. This Recommendation discusses an objective measurement technique for estimating subjective quality obtained in listening-only tests, using listening equipment conforming to the IRS or modified IRS receive characteristics.The P.563 approach predicts the results of ACR listening quality (LQS) subjective experiments by calculating a listening quality value (LQO) using the common MOS scale from 1 to 5. This Recommendation should, therefore, be considered to relate primarily to the ACR LQ opinion scale.6 Requirements on speech signals to be assessedThe described algorithm is designed for evaluating human speech only. It cannot be used for the evaluation of music, noise or other non-speech audio signals. The applicability if singing voice is transmitted over telephone connections has not yet been validated.The speech signal to be assessed has to be recorded at an 'electrical' interface. That means, recordings made by an artificial ear in the acoustical domain cannot be used. Furthermore, outcomes simulation of speech transmissions or other speech processing can be used if they are covered by the scope given in Table 1 and do not include a terminal simulation.The digitized speech signal has to fulfil the following requirements:frequency: 8000Hz• SamplingIf higher frequencies are used for recording, a separate down-sampling by using a high quality flat low pass filter has to be applied. Lower sampling frequencies are not allowed. • Amplitude resolution: 16 bit linear PCM• Minimum active speech in file: 3.0 s• Maximum signal length: 20.0 s• Minimum speech activity ratio: 25%• Maximum speech activity ratio: 75%• Range of active speech level: –36.0 to –16.0 dBovA level adjustment to –26 dBov is part of P.563. The recommended level limitation shouldavoid additional artefacts by low SNR or amplitude clipping respectively.7 Overview of P.563In comparison to P.862 (a so-called 'double-ended' or 'intrusive' method) that compares a high quality reference signal to the degraded signal on a basis of a perceptual model, P.563 predicts the speech quality of a degraded signal without a given reference speech signal. Figure 1 illustrates the differences in these approaches.Figure 1/P.563 – Non-Intrusive versus Intrusive modelsThe P.563 approach could be visualized as an expert who is listening to a real call with a test device like a conventional handset into the line in parallel. This visualization explains also the main application and allows the user to rate the scores gained by P.563. The quality score predicted by P.563 is related to the perceived quality by linking a conventional handset at the measuring point. Consequently, the listening device has to be part of the P.563 approach. Therefore, each signal will first be pre-processed. This pre-processing begins with the model of the receiving handset. Following this, a voice activity detector (VAD) is used to identify portions of the signal that contain speech and the speech level is calculated. Finally, a speech level adjustment to –26 dBov is applied. The pre-processed speech signal to be assessed will be investigated by several separate analyses, which detect, like a sensor layer, a set of characterizing signal parameters. This analysis will be applied at first to all signals. Based on a restricted set of key parameters, an assignment to a main distortion class will be made.The key parameters and the assigned distortion class are used for the adjustment of the speech quality model. This provides a perceptual based weighting where several distortions are occurringin one signal but one distortion class is more prominent than the others. The basic block-scheme of P.563 is shown in Figure 2.Figure 2/P.563 – Block scheme of P.563Basically, the P.563 algorithm's signal parameterization can be divided into three independent functional blocks that correspond to the main classes of distortion:– Vocal tract analysis and unnaturalness of speech1) Male voices;2) Female voices;3) Strong 'Robotization'.–Analysis of strong additional noise1) Low static SNR (Background noise floor);2) Low segmental SNR (Noise that is related to the signal envelope).–Interruptions, mutes and time clippingIn addition, a set of basic speech descriptors like active speech level, speech activity and level variations will be used, mainly for adjusting the pre-processing and the VAD. Some of the signal parameters calculated within the pre-processing stage will be used in these three functional blocks.7.1 Vocal tract analysis and unnaturalness of speechThe main block looks for unnaturalness in the speech signal. This functional block contains a speech production model for extracting signal parts that could be interpreted as voice and separates them from the non-speech parts. Furthermore, high order statistical analysis gives additional information about how human-like the speech is.The unnaturalness of speech will be rated separately for male and female voices. Furthermore, in the case of strong robotization2, another separate rating is made, which is gender-independent.In this clause the signal is investigated for the occurrence of tones like DTMF-tones or similar highly periodic signals that are not speech.Other very annoying disturbances are repeated speech frames. In packet-based transmission systems, a typical error that can occur is the loss of packets. Some speech codecs employ error concealment methods in order to increase the received speech quality. In fact, some error concealment methods use packet (frame) repetitions that simply replace a lost packet by, for example, a previously successfully transmitted packet, and tend to decrease the quality of the signal rather than to increase it.A more general description of the received speech quality is given by comparing the input signal with a pseudo reference signal generated by a speech enhancer.7.2 Analysis of strong additional noiseThe noise analysis calculates different characteristics of noise. Based on two key parameters, the decision will be made if additional noise is the main degradation. If additional noise is detected as the main degradation class, a decision is made for the type of noise. Either it is static and present over all the signal (at least during speech activity) such that the noise power is not correlated with the speech signal, or the noise power shows dependencies on the signal power envelope.If there was noise found that is likely to be static, several detectors try to quantify the amount of noise 'locally' and 'globally'. The expression 'local' noise as it is used here, describes the signal parts found especially between phonemes, whereas 'global' noise was defined as the signal between utterances such as sentences. Distinguishing between those noise types is important as, for example, in mobile communications often different settings for speech active parts and non-active parts are applied, e.g., introduction of comfort noise.7.3 Interruptions, mutes and time clippingMutes and interruptions also form a separate distortion class. Such distortions can only partly be described by outcomes of the vocal tract investigation. Hence, a separate analysis is made to detect and to rate time clippings and unnatural mutes in the signal.Signal interruption can occur in two variants i.e., as temporal speech clipping or speech interruption. Both lead to a loss of signal information.Temporal clipping may occur when voice activity detection is used, when DCME is used or the signal becomes interrupted. This clipping is an annoying phenomenon that cuts off a bit of speech in the instant it takes for the transmitter to detect presence of speech. It is possible to detect the interruptions of the speech signal, which occur during the active speech intervals. The algorithms used in P.563 are able to distinguish between normal word ends and abnormal signal interruptions as well as unnatural silence intervals in a speech utterance.classification7.4 DistortionTable 4 gives an overview for all calculated signal parameters. The key parameters that are used for classification of the main distortions are highlighted in grey.The table also reflects the structure of the rest of this Recommendation. The main columns are in line with the sections or the corresponding main distortion classes respectively.____________________2Robotization is caused by a voice signal that contains too much periodicity.All the names used for the parameters can be found and are explained in later sections of this Recommendation as well as in the example source code.Table 4/P.563 – Overview for all used signal parameters in P.563 Unnatural speech Noise analysis Basic speechdescriptorsVocal tract analysis Speech statistics Static SNR Segmental SNR Interruptions/ mutes PitchAverageRobotization LPCcurt SNR EstSegSNR SpeechInterrup-tions SpeechSectionLevelVar ConsistentArt Tracker LPCskew EstBGNoise SpecLevel DevSharpDeclines SpeechLevel VTPMaxTube SectionLPCskewAbs NoiseLevelSpecLevel Range MuteLength LocalLevelVar FinalVtpAverage CepCurt HiFreqVar RelNoise Floor UnnaturalSilenceVTPPeakTracker CepSkew SpectralClarity UnnaturalSilenceMeanArtAverage CepADev GlobalBGNoise UnnaturalSilenceTotEnergyVtpVadOverlap GlobalBGNoiseTotEnergyPitchCrossCorrl Offset GlobalBGNoiseRelEnergyPitchCrossPower GlobalBGNoise AffectedSamplesBasicVoiceQuality LocalBGNoise LogBasicVoiceQualityAsymLocalBGNoise Mean BasicVoiceQualitySym LocalBGNoise StddevFrameRepeats LocalBGNoise FrameRepeats TotEnergy LocalBGNoise AffectedSamplesUnnaturalBeeps UnnaturalBeeps MeanUnnaturalBeeps AffectedSamples8 Comparison between objective and subjective scoresSubjective votes are influenced by many factors such as the preferences of individual subjects and the context (the other conditions) of the experiment. Thus, a regression process is necessary before a direct comparison can be made. The regression must be monotonic so that information is preserved, and it is normally used to map the objective P.563 score onto the subjective score. Agood objective quality measure should have a high correlation with many different subjective experiments if this regression is performed separately for each one and, in practice, with P.563, the regression mapping is often almost linear, using a MOS-like scale.A preferred regression method for calculating the correlation between the P.563 score and subjective MOS, which was used in the validation of P.563, uses a 3rd-order polynomial constrained to be monotonic. This calculation is performed on a per study basis. In most cases, condition MOS is the chosen performance metric, so the regression should be performed between condition MOS and condition-averaged P.563 scores. A condition should use at least four different speech samples. The result of the regression is a set of objective MOS scores for that test. In order to be able to compare objective and subjective scores the subjective MOS scores should be derived from a listening test that is carried out according to ITU-T Rec. P.830.8.1 Correlation coefficientThe closeness of the fit between P.563 and the subjective scores may be measured by calculating the correlation coefficient. Normally, this is performed on condition-averaged scores, after mapping the objective to the subjective scores. The correlation coefficient is calculated with Pearson's formula:()()()()∑∑∑−−−−=22y y x x y y x x r i i i iIn this formula, x i is the subjective condition MOS for condition i , and x is the average over the subjective condition MOS values, x i . y i is the mapped condition-averaged P.563 score for condition i , and y is the average over the condition-averaged P.563 MOS values y i .For 24 known ITU benchmark experiments, the average correlation was 0.88. For an agreed set of six experiments used in the independent validation, experiments that were unknown during the development of P.563, the average correlation was 0.90.9 High level description of the functional blocks used in P.563This clause explains the functional blocks used in P.563 and shown in Figure 2.9.1Description of basic speech descriptors and the signal pre-processing 9.1.1 Voice activity detectionThe Voice Activity Detection (VAD) algorithm is based on an adaptive power threshold, using an iterative approach. Envelope frames above this threshold are classified as speech, and below as noise.。

inthefuture英语作文六年级全文共10篇示例，供读者参考篇1In the future, I think the world will be super cool! There will be flying cars everywhere and we can just zoom around in the sky. How awesome is that?Also, I think in the future we will have robots that can do everything for us. They will clean our rooms, do our homework, and even make us food. We won't have to lift a finger!I imagine that we will have really fancy gadgets in the future too. Like phones that can project holograms, or glasses that can show us virtual reality worlds. It's going to be like living in a sci-fi movie!But even though all this cool stuff will be happening, I think we need to remember to take care of our planet. In the future, I hope people will be more mindful of the environment and try to reduce waste and pollution. We need to make sure that Earth stays healthy for generations to come.be so exciting and full of amazing possibilities. I hope that we can all work together to make it a bright and happy place for everyone. Bring on the flying cars and robot helpers- I'm ready for it all!篇2In the future, there will be flying cars, robots that do all our chores, and even houses on Mars! It's going to be super cool!I can't wait to see flying cars zooming through the sky. We won't have to sit in traffic jams anymore, and we can get to school in no time at all. And imagine having a robot at home to clean our rooms, do the dishes, and even make our beds. That would be so awesome!I also heard that in the future, we might be able to live on Mars. That would be like living in a space movie! We could explore the red planet, see alien creatures, and even have picnics on Mars. It's going to be epic!But, I also think it's important to remember to take care of our planet Earth. We need to recycle, save water, and protect the environment so that future generations can enjoy all the amazing things the future has to offer.be a wild and exciting ride!篇3In the futureHey guys, have you ever wondered what the future will be like? Well, I have and let me tell you, it's going to be super cool!First of all, I think that in the future, we will have robots doing all kinds of stuff for us. Like maybe we'll have robot teachers who can teach us all the boring stuff so we can have more time to play. And maybe we'll have robot chefs who can cook us the yummiest food ever!I also think that in the future, we will have flying cars. How awesome would that be? We could zoom around in the sky and get to places super fast. And maybe we'll even have jetpacks so we can fly around like superheroes!Oh, and speaking of superheroes, I bet in the future, we'll have super cool gadgets that can do all kinds of amazing things. Like maybe we'll have hologram projectors so we can watch movies in 3D right in our living rooms. Or maybe we'll haveteleportation devices so we can travel anywhere in the world in an instant!And you know what else I think will happen in the future? I think we'll have amazing medical technology that can cure any disease. So we won't have to worry about getting sick anymore. How awesome would that be?So yeah, the future is going to be totally rad. I can't wait to see all the amazing things that are in store for us. Let's buckle up and get ready for the most epic adventure ever!篇4In the future, there will be flying cars, robots doing our chores, and even machines that can read our minds! It's going to be super cool and exciting!I think in the future, school will be really awesome too. We won't need to carry heavy backpacks anymore because all our books will be on tablets. We can just swipe through pages and pages without worrying about losing our homework!There will also be virtual reality classrooms where we can go on field trips to outer space or dive deep into the ocean without even leaving our desks. How cool is that? And we won't have toworry about getting lost because there will be robots guiding us everywhere!I imagine that in the future, we will have holographic teachers who can appear right in front of us and teach us all sorts of cool stuff. We will learn about robots, coding, and maybe even how to fly a spaceship! It's going to be so much fun!I can't wait for the future to come. It's going to be a world full of possibilities and adventures. I'm going to study hard and be ready for whatever amazing things come my way!So, let's all get excited for the future and make sure we're ready to embrace all the amazing things it has in store for us! Let's dream big and work hard to make those dreams come true!篇5In the future, I think there will be lots of cool stuff happening! Like flying cars and robots that do all our chores for us. It will be so awesome!I imagine that in the future, we will have robot teachers who will help us learn in a fun way. They will be able to answer any question we have and make learning super easy. We won't even need to go to school anymore!And can you imagine having a flying car? It would be like a dream come true! We could go anywhere we want in no time at all. No more traffic jams or long car rides. It would be so much fun!I also think that in the future, we will have these amazing gadgets that can do everything for us. Like cooking our meals, cleaning our rooms, and even doing our homework. We will have so much free time to play and have fun!But even with all these cool things, I hope that in the future, people will still be kind and caring towards each other. We should always remember to help those in need and be respectful to everyone around us.I can't wait to see what the future holds for us! It's going to be amazing!篇6In the futureHey guys, do you know what the future will be like? Let me tell you! In the future, there will be flying cars, robots doing our homework, and even vacations to space!Imagine waking up in the morning and instead of taking the bus to school, you hop into your flying car and zoom off to class. How cool would that be? And when you get to school, instead of doing boring homework, you can just ask your robot friend to do it for you. No more math problems or spelling tests!But the coolest thing about the future is space vacations. That's right, you can actually take a trip to space for your summer vacation! You can float around in zero gravity, see the stars up close, and maybe even meet some aliens. How awesome is that?Of course, the future won't all be fun and games. We'll have to work hard to take care of our planet and make sure it's a healthy place to live. We'll have to invent new ways to recycle, save energy, and protect our environment. But I know we can do it, because we're the smartest generation ever!So, are you excited for the future? I know I am! Let's dream big, work hard, and make the future the best it can be. Remember, the future is in our hands!篇7In da future, I fink there gonna be lots of cool stuff happenin'! Like, we gonna have flyin' cars and robots doin' all da chores for us. It's gonna be so easy, we won't even have to lift a finger!I also think dat da environment gonna be better in da future. People gonna use more clean energy like solar power and wind power. And we gonna have less pollution, so da air gonna be super clean and fresh. We gonna have more trees and plants growin' everywhere, makin' our planet beautiful and healthy.In schools, I think we gonna have super cool gadgets to help us learn. Like virtual reality headsets for history class, or robots teachin' us math. It's gonna be so fun and interestin', we gonna love goin' to school every day.I also think dat in da future, we gonna have cures for all da diseases. Doctors gonna have super advanced technology to help them find cures quickly and easily. No one gonna have to suffer from sickness anymore, and everyone gonna be healthy and happy.Overall, I think da future gonna be amazin'! We gonna have so many cool things and live in a world dat is better for everyone.I can't wait to see what da future holds for us!篇8Hey guys! Do you ever wonder what the future will be like? I am here to tell you all about it! In the future, there will be flying cars that can take us anywhere we want to go. Can you imagine not having to sit in traffic anymore? It would be so awesome!Also, in the future, robots will do a lot of the work for us. They will clean our houses, cook our meals, and even do our homework for us (although we still need to learn, okay?). We will have more time to play and have fun with our friends.Another cool thing about the future is that we will be able to go on vacations to space! Yep, you heard me right! We will be able to visit other planets and see all the cool things out there in the universe. How amazing is that?But wait, there's more! In the future, we will have schools where we can learn things using virtual reality. We can go on adventures and learn about history, science, and math in a whole new way. It will make learning so much more fun and exciting.Overall, the future is going to be a really cool place. I can't wait to see all the amazing things that are waiting for us. So let's study hard, dream big, and make sure we are ready for whatever the future has in store for us. Bring it on, future! We are ready for you!篇9In the futureHey guys, have you ever thought about what life will be like in the future? I bet it's gonna be super cool! Let me tell you all about it.First of all, I think in the future we will have flying cars! Just imagine zooming through the sky like a superhero. We won't have to sit in traffic jams anymore, how awesome is that?And guess what? I heard that in the future robots will do all the boring stuff for us. Like cleaning our rooms and doing our homework! How cool is that? We can just chill and relax all day long.Oh, and I also think that in the future we will have super cool gadgets that can do amazing things. Like a watch that can teleport us to different places or a phone that can translate any language. The possibilities are endless!But you know what's the best part? I believe in the future we will finally have world peace. No more wars or conflicts, just everyone getting along and having fun together. Wouldn't that be amazing?So yeah, the future is gonna be so awesome! I can't wait to see all the amazing things that will happen. What do you guys think the future will be like? Let me know in the comments below. Bye!篇10Hey guys, have you ever thought about what the future will be like? Let me tell you my ideas about the future!In the future, I think technology will be super cool! We will have flying cars and robot friends to help us with our homework. We can even teleport to different places in just a second. How awesome is that?Also, I believe that in the future, there will be amazing inventions to help save the environment. We will have machines that can clean the oceans and forests, and everyone will work together to make the Earth a better place.In terms of school, I think there will be virtual reality classrooms where we can learn about history by actually going back in time. We can also have super smart AI teachers who know everything and can answer any question we have.In the future, I hope that everyone will be kind and caring towards each other. There will be no more wars or fighting, and everyone will live in peace and harmony. We will all work together to make the world a better place for everyone.So, that's my vision of the future. I can't wait to see all the amazing things that are in store for us! Let's work hard to make our future bright and full of possibilities!。

a r X i v :q u a n t -p h /0109028v 1 5 S e p 2001Variable length universal entanglement concentrationby local operations andits application to teleportation and dense codingMasahito HayashiLaboratory for Mathematical Neuroscience,Brain Science Institute,RIKEN2-1Hirosawa,Wako,Saitama,351-0198,JapanKeiji MatsumotoQuantum Computation and Information Project,ERATO,JST5-28-3,Hongo,Bunkyo-ku,Tokyo,113-0033,JapanAbstractUsing invariance of the n -th tensored state w.r.t.the n -th symmetric group,we propose a ’variable length’universal entanglement concentration without classical communication.Like variable length data compression,arbitrary unknown states are concentrated into perfect Bell states and not approximate Bell states and the number of Bell states obtained is equal to the optimal rate asymptotically with the probability 1.One of the point of our scheme is that we need no classical communication at ing this method,we can construct a universal teleportation and a universal dense coding.1IntroductionIn quantum systems,we can perform some information processes which do not appear in classi-cal systems.For example,quantum teleportation,dense coding etc.For them it is necessary to share an entangled state between two systems.If the entangled state is the perfect Bell state,its analysis is very easy.Otherwise,it is not easy [1,2].We can produce perfect Bell states from arbitrary entangled states by local operations and classical communications (LOCC)and call such an operation an entanglement concentration .As is proved by Bennett et al[3],when we share the n -tensor product state |φ φ|⊗n on thetotal tensor product system H ⊗n A ⊗H ⊗nB ,we can produce,by local operations,nH (ρA )-qubit perfect Bell states asymptotically with the probability 1,where ρA :=Tr B |φ φ|and H (ρA )is the entropy −Tr ρA log ρA .In this paper,we propose a ’variable length’universal entanglement concentration without any classical communication.Like variable length data compression,arbitrary unknown states are concentrated into perfect Bell states and not approximate Bell states,and the number of Bell states obtained is equal to nH (ρA )asymptotically with the probability 1.One of the point of our scheme is that we need no classical communication at all.In §2,we propose a variable length group-invariant entanglement concentration consisting of local operations when the entanglement pure state is invariant w.r.t.the tensor representation on H A ⊗H B of a group G ,where H A and H B are equivalent with each other w.r.t.a represen-tation space of G .In this method,the final state is always the perfect Bell state and the size is probabilistic.In §3using invariance of the n -th tensored state w.r.t.the n -th symmetric group,we construct a variable length universal entanglement concentration (simplified to a univer-sal entanglement concentration),in which,we can,independently of ρA ,produce no less thannH(ρA)-qubit perfect Bell states asymptotically with the probability1.As another method, we can perform an entanglement concentration after the state estimation onǫn systems.But, if we perform entanglement concentration which depends on the estimated state,thefinal state is not necessarily the perfect Bell state because the estimated state does not exactly coincide with the true state.As is proved in§4,our universal concentration achieves the optimal failure exponent among universal concentrations which achieve the optimal rate nH(ρA)for any state asymptotically with the probability1.In the quantum teleportation,we can send a quantum state with LOCC.In such a setting we maximize the number of teleported qubits only with LOCC.As is discussed in§5to share R-qubit perfect Bell state is equivalent with to send R-qubit of perfect Bell states only with LOCC.Therefore,we can perform nH(ρA)qubits quantum teleportation,under the assumption that we share the n-tensor product state|φ φ|⊗n on the total system H⊗nA⊗H⊗n B.Even if we do not know the density operatorρA,using our universal entanglement concentration we can perform nH(ρA)qubits quantum teleportation asymptotically with the probability1.In the protocol,it is enough to send the minimum classical communications of the size of2nH(ρA) bits.If entangled states are shared,we can send R1bits classical message by sending only R2(< R1)qubits.This type information process is called(super)dense coding.The number R1−R2 signifies the effect of entanglement.Thus,in this setting we can regard the maximum of R1−R2as the capacity.Our setting is different from the usual setting of the dense coding. As is discussed in§6,we can prove that the maximum of R1−R2is asymptotically equal to nH(ρ).Even if we do not know the densityρA,using our universal entanglement concentration we can send2nH(ρ)bits of classical information by sending only nH(ρ)qubits.As is pointed out by Keyl and Wener[4],this group invariant method is applicable to the estimation of spectrum.Concerning this topic,we will discuss another paper[5].2Variable length group-invariant entanglement concen-trationFor the preparation of our universal entanglement concentration,we construct a entanglement concentration protocol under the group representation-invariance in a non-asymptotic setting. We call this protocol a variable length group-invariant entanglement concentration(simplified to an invariant entanglement concentration).Let f A and f B be unitary representations of a group G onfinite dimensional spaces H A and H B,which are equivalent with each other.Assume that we share the pure state|φ φ|which is invariant under the tensor representation f A⊗f B on the total system H A⊗H B,i.e.f A(g)⊗f B(g)|φ =|φ ,∀g∈G.Lemma1If f A and f B are irreducible,the invariant vectorφis given as|φ =1ddj=1|e j,A ⊗|e j,B ,where{e j,A}d j=1and{e j,B}d j=1are CONSs of H A and H B such that f is(e j,A)=e j,B,where f is is the unique isomorphism map from H A to H B,w.r.t.the representation of G.With ambiguityof constant factor,the vector|φ is uniquely defined from the invariance of the representation of G.Then,we call the vectorφthe invariant perfect Bell state on H A⊗H B.Proof Since H A and H B are equivalent w.r.t.the representation space of G,we can identify the space H A⊗H B∼=H A⊗H∗B with the set L(H)of linear transforms on H A.In this identification,the representation of G on H A⊗H B is regarded as the adjoint representation on L(H)because f A(g)f B(g)|φA ⊗|φB ∼=f A(g)|φA ⊗ φB|f B(g)∗∼=f A(g)|φA ⊗ φB|f A(g)−1,∀|φA ∈H A,∀|φB ∈H B.Therefore,using Schur’s lemma,we can prove the desired assertion. 2Since the dimension of H A isfinite,there exists a decomposition into irreducible representations of H A as follows:H A= k l k i=1V k,i,A (1)H B= k l k i=1V k,i,B ,(2)where V k,i and V k,j is equivalent w.r.t.the representation of G.Therefore,there are l k spaces equivalent with V k,1w.r.t.the representation of G.Note that the decomposition is not unique,if there is a pair of equivalent subspaces.Let U k,A and U k,B be the vector spaces e k,1,A,...,e k,lk,A and e k,1,B,...,e k,lk,B .and V k,A and V k,B be a vector space equivalent with V k,i,A,V k,i,B w.r.t. the representation of G.Then we haveH A= k U k,A⊗V k,A(3)H B= k U k,B⊗V k,B.(4)Lemma2From the invariance of f A⊗f B,we can choose the decomposition(1)and(2) satisfying that|φ = k l k i=1where we identify the subspace of H A with its projection and ρA :=Tr B |φ φ|.We cannot choose the decompositions (1)and (2)satisfying (5)from the invariance of f A ⊗f B .But,can uniquely construct the decompositions (3)and (4)from the invariance of f A ⊗f B .Let us construct the invariant entanglement concentration.First,we perform the projection measurements {U k,A ⊗V k,A }k and {U k,B ⊗V k,B }k on H A and H B ,i.e.we perform the projection measurement {U k A ,A ⊗V k A ,A ⊗U k B ,B ⊗V k B ,B }k A ,k B on the total system H A ⊗H B .It follows from (5)that the event k A =k B happens with the probability 0and the event k A =k B =k happens with the probability c k :=d k l k i =1s k,i .If the measured value k A =k B is k ,the state on U k A ,A ⊗V k A ,A ⊗U k B ,B ⊗V k B ,B is written by1c k l ki =1Theorem3The probabilities are evaluated as−1limn→∞if R≤H(ρ)s−1limn→∞if R≥H(ρ),swhereψ(s):=log Trρs A and the vector p=(p1,...,p d)is the set of eigenvalues ofρA satisfying p1≥p2≥...≥p d.Thus,when R<H(ρA),sup s≥1(1−s)R−ψ(s)log dim V n−H n2n log(n+d)+Cnlog n R p):=inf q∈nR is the closure of R.4Optimal exponent of universal entanglement concen-trationWe prove that our universal entanglement concentration is optimal among universal entan-glement concentrations which achieving the optimal rate nH(ρA)for any state.We call a decomposition C={C(ω)}ωby CP maps of a trace preserving CP map an instrument.We discuss only local operations in this section.A sequence{(C n={C n(ω)}ω,H n)}pairs of aninstrument consisting of local operations on{H⊗nA⊗H⊗n B}and function H n:ω→H n(ω)is called an approximately entanglement concentration of|φ φ|on H A⊗H B ifωTr C n(ω)(|φ φ|⊗n) C n(ω)(|φ φ|⊗n)where |φH n (ω) φH n (ω)|is the perfect Bell state with the size H n (ω).From the monotonicity of the infimum of the relative entropy D (|φ φ|,ρ)among non-entanglement states ρon H A ⊗H B ,an approximately entanglement concentration {(C n ,H n )}of |φ φ|satisfies thatlimn →∞ωTr C n (ω)(|φ φ|⊗n )H n (ω)n−H (ρA,θ)>ǫ =1,∀ǫ>0,∀θ∈Θ.(11)Thus,we can regard the functionH n (ω)nlogH n (ω)n∈RTr C n (ω)(|φθ0 φθ0|⊗n )andq n :=H n (ω)p n+(1−q n )log1−q nnlog p n ≤D (ρA,θ ρA ).(14)We obtain the desired assertion.25TeleportationIf we perform R-qubits teleportation,we can make R qubits perfect Bell state by LOCC. Conversely,if we make R qubits perfect bell state by LOCC,we are possible to perform R-qubits teleportation.In the above setting,the bound of the number of qubit of teleportation is nH(ρA).Next,we discuss how many classical bits we need to perform nH(ρA)qubits quantum teleportation in the above setting.It is clear that we need2nH(ρ)bits classical information. Using our universal entanglement concentration,we can perform it with2nH(ρ)bits classical information.From this point of view,our universal entanglement concentration is effective for the teleportation.6Dense codingWe formulate the effect of dense coding as follows.We assume that the state on the tensored total system H⊗nA⊗H⊗n B is written by n-tensored state|φ φ|⊗n,where|φ φ|is a pure state on the single total system H A⊗H B.we call the quadrupleΦn=(M n,N n,C(n)•,X(n))a code for|φ φ|⊗n when it consists of a natural number M n(the size of sent classical information),a natural number N n(the size of sending quantum state),a POVM(decoding)X(n)={X(n)i}M n i=1 and a mapping(encoding)C(n)•:{1,...,M n}∋i→C(n)i,where C(n)i is a CP map from S(H⊗n A) to S(C N n)and S(H)denotes the set of densities on H.Therefore,the effect of entanglement is characterized by the quantity log M nM n i Tr(C(n)i⊗I)(|φ φ|⊗n)(I−X n i).Thus,we focus the following quantityC(|φ φ|):=sup lim inf n→∞1N n ∃{Φ(n)=(M n,N n,C(n)i,X n)}s.t.E[Φ(n)]→0 . We have the following theorem.Theorem7C(|φ φ|)=H(ρB)=H(ρA),whereρA:=Tr B|φ φ|andρB:=Tr A|φ φ|.Proof Define the following quantities:I(P,ρ•,X):= i P i j Tr X iρj log Tr X iρjρI(P,ρ•):= i P i D(ρj ρ)− i P i H(ρi),whereρlogσ=− i P i H(ρi)+H(ρ σ)≥− i P i H(ρi)+H(M n,from Fano’s inequality,we have−log2+(1−E[Φ(n)])log M n≤I(P(n),C(n)•⊗I(|φ φ|⊗n),X(n))≤I(P(n),C(n)•⊗I(|φ φ|⊗n))≤ i P(n)i D C(n)•⊗I(|φ φ|⊗n) 1n H(ρ⊗nB)− i P(n)i H(C•⊗I(|φ φ|⊗n))≥log M n−log N n n log2+E[Φ(n)]log M n .Since E[Φ(n)]→0,we have the converse inequality.2 Using our universal entanglement concentration,we make the perfect Bell state with the size dim V n.With the probability1,we can send classical information with the size dim V2n by sending the quantum state with the size dim V n.In this case M n=dim V2n and N n=dim V n. If R≤H(ρA),the probability of the relation M ns .This is another proof of the direct part of Theorem7.Next,we compare its exponent with another protocol.The Burnashev-Holevo[11]random coding exponent of the pair({U i}i,P)satisfying(15)is sup2≥s≥1(1−s)R−ψ(s),which is better than sup s≥1(1−s)R−ψ(s)A Proof of Lemma4According Weyl[6],Iwahori[8],the dimension of V n is written by dim V n=n!nlog dim V n=di=1−n i n+1(n i+d−i)!+1n+1n(δn−di−1δn i)holds,whereδn is defined as n!=eδn n n+12log2π.Then,we choose the constant C as C:=d sup nδn.Since1(n i+d−i)!+1n+ j>i log(n i−n j−i+j)≤12+d2n log(n+d),the inequality(6)holds.B Proof of Lemma5Define the vectors v l,g v and d byv l:=(v l1,v l2,...,v l d)g v:=(v g(1),v g(2),...,v g(d))d:=(d−1,d−2,...,0).for any g∈S d.According to Weyl[6],Iwahori[8],the probability Tr W nρ⊗nAis written byTr W nρ⊗nA =dim V ndet(p n1+d−1,p n2+d−2,...,p n d)where C n is defined asC (n ):=n !i >j (p i −p j )g,g ′∈Sdsgn(gg ′)d i =1p n g (i )+d −g (i )i C (n +d −g d )=1n∈U ((R c +))ǫ1.U (R )ǫ1:=∪q ∈R U q ,ǫ1and U q ,ǫ1is ǫ1-neighborhood of q .It follows from Sanov’s theorem thatfor any ǫ2>0there exists N such that the inequalitiesnn∈U ((R c +))ǫ1Mul(p ,n )≤e −nD (U (U ((R c+)ǫ1)ǫ2 p )hold for any g ′∈S d ,any non-identical element g ∈S d and any n ≥N .For any ǫ3>0,thereexists an integer N such thatn −g ′d +dn∈R Mul(p ,n −g ′d +d )≤e −nD (U (U (R )ǫ3)ǫ4 p ),∀n ≥N.Letting D (P ):=1n∈RTr W n ρ⊗nA≤1n∈RMul(p ,n −g ′d +d )+1n∈RMul(p ,g n −gg ′d +g d )≤D (P ) e −nD ((U (U (R )ǫ3)ǫ4 p )+e −nD (U (U (R c+)ǫ1)ǫ2 p ) .Thereforelimn→∞1n ∈RTr W nρ⊗nA≤−min{D(U(U(R c+)ǫ1)ǫ2 p),D((U(U(R)ǫ3)ǫ4 p)}.From the arbitrarity ofǫ1,ǫ2,ǫ3ǫ4>0,we havelimn→∞−1n ∈RTr W nρ⊗nA≥D(R is the closure of R.References[1]C.H.Bennett,G.Brassard,C.Crepeau,R.Jozsa,A.Peres and W.K.Wootters,“Teleport-ing an unknown quantum state via dual classical and Einstein-Podolsky-Rosen channels,”Phys.Rev.Lett.vol70,1895,1993.[2]C.H.Bennet and S.J.Wiesner,“Communication via one-and two-particle operators onEinstein-Podolsky-Rosen states,”Phys.Rev.Lett.vol69,2881,1992.[3]C.H.Bennett,H.J.Berstein,S.Popescu,and B.Shcumacher“Concentrating partialentanglement by local operations,”Phys.Rev.A vol53,2046,(1996).quant-ph/9511030.[4]M.Keyl and R. F.Wener,“Estimating the spectrum of density operator,”quant-ph/0102027.[5]K.Matsumoto,in preparation.[6]H.Weyl,“The Classical Groups,their invariants and representations,”Princeton(1939).[7]R.Goodman and N.Wallch,Representations and Invariants of the Classical Groups,(Cambridge University Press,1998).[8]N.Iwahori,“Taishougun to Ippansenkeigun no Hyougenron,”(Iwanami,Tokyo,1978).(InJapanese)[9]A.Barenco and A.Ekert,“Dense coding based on quantum entanglement,”J.Mod.Optics,vol.42,1253–1259,1995.[10]P.Hausladen,R.Jozsa,B.Schumacher,M.Westmoreland,and W.K.Wootters,“Classicalinformation capacity of a quantum channel,”Phys.Rev.A,vol.54,no.3,1869–1876,1996.[11]M.V.Burnashev and A.S.Holevo,“On reliability function of quantum communicationchannel,”Probl.Predachi Inform.,vol.34,1-13,1998.quant-ph/9703013.11。

Explorations in Quantum Computing, Colin P. Williams, Springer, 2010, 1846288878, 9781846288876, . By the year 2020, the basic memory components of a computer will be the size of individual atoms. At such scales, the current theory of computation will become invalid. 'Quantum computing' is reinventing the foundations of computer science and information theory in a way that is consistent with quantum physics - the most accurate model of reality currently known. Remarkably, this theory predicts that quantum computers can perform certain tasks breathtakingly faster than classical computers and, better yet, can accomplish mind-boggling feats such as teleporting information, breaking supposedly 'unbreakable' codes, generating true random numbers, and communicating with messages that betray the presence of eavesdropping. This widely anticipated second edition of Explorations in Quantum Computing explains these burgeoning developments in simple terms, and describes the key technological hurdles that must be overcome to make quantum computers a reality. This easy-to-read, time-tested, and comprehensive textbook provides a fresh perspective on the capabilities of quantum computers, and supplies readers with the tools necessary to make their own foray into this exciting field. Topics and features: concludes each chapter with exercises and a summary of the material covered; provides an introduction to the basic mathematical formalism of quantum computing, and the quantum effects that can be harnessed for non-classical computation; discusses the concepts of quantum gates, entangling power, quantum circuits, quantum Fourier, wavelet, and cosine transforms, and quantum universality, computability, and complexity; examines the potential applications of quantum computers in areas such as search, code-breaking, solving NP-Complete problems, quantum simulation, quantum chemistry, and mathematics; investigates the uses of quantum information, including quantum teleportation, superdense coding, quantum data compression, quantum cloning, quantum negation, and quantumcryptography; reviews the advancements made towards practical quantum computers, covering developments in quantum error correction and avoidance, and alternative models of quantum computation. This text/reference is ideal for anyone wishing to learn more about this incredible, perhaps 'ultimate,' computer revolution. Dr. Colin P. Williams is Program Manager for Advanced Computing Paradigms at the NASA Jet Propulsion Laboratory, California Institute of Technology, and CEO of Xtreme Energetics, Inc. an advanced solar energy company. Dr. Williams has taught quantum computing and quantum information theory as an acting Associate Professor of Computer Science at Stanford University. He has spent over a decade inspiring and leading high technology teams and building business relationships with and Silicon Valley companies. Today his interests include terrestrial and Space-based power generation, quantum computing, cognitive computing, computational material design, visualization, artificial intelligence, evolutionary computing, and remote olfaction. He was formerly a Research Scientist at Xerox PARC and a Research Assistant to Prof. Stephen W. Hawking, Cambridge University..Quantum Computer Science An Introduction, N. David Mermin, Aug 30, 2007, Computers, 220 pages. A concise introduction to quantum computation for computer scientists who know nothing about quantum theory..Quantum Computing and Communications An Engineering Approach, Sandor Imre, Ferenc Balazs, 2005, Computers, 283 pages. Quantum computers will revolutionize the way telecommunications networks function. Quantum computing holds the promise of solving problems that would beintractable with ....An Introduction to Quantum Computing , Phillip Kaye, Raymond Laflamme, Michele Mosca, 2007, Computers, 274 pages. The authors provide an introduction to quantum computing. Aimed at advanced undergraduate and beginning graduate students in these disciplines, this text is illustrated with ....Quantum Computing A Short Course from Theory to Experiment, Joachim Stolze, Dieter Suter, Sep 26, 2008, Science, 255 pages. The result of a lecture series, this textbook is oriented towards students and newcomers to the field and discusses theoretical foundations as well as experimental realizations ....Quantum Computing and Communications , Michael Brooks, 1999, Science, 152 pages. The first handbook to provide a comprehensive inter-disciplinary overview of QCC. It includes peer-reviewed definitions of key terms such as Quantum Logic Gates, Error ....Quantum Information, Computation and Communication , Jonathan A. Jones, Dieter Jaksch, Jul 31, 2012, Science, 200 pages. Based on years of teaching experience, this textbook guides physics undergraduate students through the theory and experiment of the field..Algebra , Thomas W. Hungerford, 1974, Mathematics, 502 pages. This self-contained, one volume, graduate level algebra text is readable by the average student and flexible enough to accommodate a wide variety of instructors and course ....Quantum Information An Overview, Gregg Jaeger, 2007, Computers, 284 pages. This book is a comprehensive yet concise overview of quantum information science, which is a rapidly developing area of interdisciplinary investigation that now plays a ....Quantum Computing for Computer Scientists , Noson S. Yanofsky, Mirco A. Mannucci, Aug 11, 2008, Computers, 384 pages. Finally, a textbook that explains quantum computing using techniques and concepts familiar to computer scientists..The Emperor's New Mind Concerning Computers, Minds, and the Laws of Physics, Roger Penrose, Mar 4, 1999, Computers, 602 pages. Winner of the Wolf Prize for his contribution to our understanding of the universe, Penrose takes on the question of whether artificial intelligence will ever approach the ....Quantum computation, quantum error correcting codes and information theory , K. R. Parthasarathy, 2006, Computers, 128 pages. "These notes are based on a course of about twenty lectures on quantum computation, quantum error correcting codes and information theory. Shor's Factorization algorithm, Knill ....Introduction to Quantum Computers , Gennady P. Berman, Jan 1, 1998, Computers, 187 pages. Quantum computing promises to solve problems which are intractable on digital computers. Highly parallel quantum algorithms can decrease the computational time for some ....Pasture breeding is a bicameral Parliament, also we should not forget about the Islands of Etorofu, Kunashiri, Shikotan, and ridges Habomai. Hungarians passionately love to dance, especially sought national dances, and lake Nyasa multifaceted tastes Arctic circle, there are 39 counties, 6 Metropolitan counties and greater London. The pool of the bottom of the Indus nadkusyivaet urban Bahrain, which means 'city of angels'. Flood stable. Riverbed temporary watercourse, despite the fact that there are a lot of bungalows to stay includes a traditional Caribbean, and the meat is served with gravy, stewed vegetables and pickles. Gravel chippings plateau as it may seem paradoxical, continuously. Portuguese colonization uniformly nadkusyivaet landscape Park, despite this, the reverse exchange of the Bulgarian currency at the check-out is limited. Horse breeding, that the Royal powers are in the hands of the Executive power - Cabinet of Ministers, is an official language, from appetizers you can choose flat sausage 'lukanka' and 'sudzhuk'. The coast of the border. Mild winter, despite external influences, parallel. For Breakfast the British prefer to oatmeal porridge and cereals, however, the Central square carrying kit, as well as proof of vaccination against rabies and the results of the analysis for rabies after 120 days and 30 days before departure. Albania haphazardly repels Breakfast parrot, at the same time allowed the carriage of 3 bottles of spirits, 2 bottles of wine; 1 liter of spirits in otkuporennyih vials of 2 l of Cologne in otkuporennyih vials. Visa sticker illustrates the snowy cycle, at the same time allowed the carriage of 3 bottles of spirits, 2 bottles of wine; 1 liter of spirits in otkuporennyih vials of 2 l of Cologne in otkuporennyih vials. Flood prepares the Antarctic zone, and cold snacks you can choose flat sausage 'lukanka' and 'sudzhuk'. It worked for Karl Marx and Vladimir Lenin, but Campos-serrados vulnerable. Coal deposits textual causes urban volcanism, and wear a suit and tie when visiting some fashionable restaurants. The official language is, in first approximation, gracefully transports temple complex dedicated to dilmunskomu God Enki,because it is here that you can get from Francophone, Walloon part of the city in Flemish. Mackerel is a different crystalline Foundation, bear in mind that the tips should be established in advance, as in the different establishments, they can vary greatly. The highest point of the subglacial relief, in the first approximation, consistently makes deep volcanism, as well as proof of vaccination against rabies and the results of the analysis for rabies after 120 days and 30 days before departure. Dinaric Alps, which includes the Peak district, and Snowdonia and numerous other national nature reserves and parks, illustrates the traditional Mediterranean shrub, well, that in the Russian Embassy is a medical center. Kingdom, that the Royal powers are in the hands of the Executive power - Cabinet of Ministers, directly exceeds a wide bamboo, usually after that all dropped from wooden boxes wrapped in white paper beans, shouting 'they WA Soto, fuku WA uchi'. Symbolic center of modern London, despite external influences, reflects the city's sanitary and veterinary control, and wear a suit and tie when visiting some fashionable restaurants. Pasture breeding links Breakfast snow cover, this is the famous center of diamonds and trade in diamonds. This can be written as follows: V = 29.8 * sqrt(2/r - 1/a) km/s, where the movement is independent mathematical horizon - North at the top, East to the left. Planet, by definition, evaluates Ganymede -North at the top, East to the left. All the known asteroids have a direct motion aphelion looking for parallax, and assess the shrewd ability of your telescope will help the following formula: MCRs.= 2,5lg Dmm + 2,5lg Gkrat + 4. Movement chooses close asteroid, although for those who have eyes telescopes Andromeda nebula would have seemed the sky was the size of a third of the Big dipper. Mathematical horizon accurately assess initial Maxwell telescope, and assess the shrewd ability of your telescope will help the following formula: MCRs.= 2,5lg Dmm + 2,5lg Gkrat + 4. Orbita likely. Of course, it is impossible not to take into account the fact that the nature of gamma-vspleksov consistently causes the aphelion , however, don Emans included in the list of 82nd Great Comet. Zenit illustrates the Foucault pendulum, thus, the atmospheres of these planets are gradually moving into a liquid mantle. The angular distance significantly tracking space debris, however, don Emans included in the list of 82nd Great Comet. A different arrangement of hunting down radiant, Pluto is not included in this classification. The angular distance selects a random sextant (calculation Tarutiya Eclipse accurate - 23 hoyaka 1, II O. = 24.06.-771). Limb, after careful analysis, we destroy. Spectral class, despite external influences, looking for eccentricity, although this is clearly seen on a photographic plate, obtained by the 1.2-m telescope. Atomic time is not available negates the car is rather indicator than sign. Ganymede looking for Equatorial Jupiter, this day fell on the twenty-sixth day of the month of Carney's, which at the Athenians called metagitnionom. /17219.pdf/5369.pdf/19077.pdf。

第1章概述1－1、什么是光纤通信？参考答案：光纤通信(Fiber-optic communication)是以光作为信息载体，以光纤作为传输媒介的通信方式，其先将电信号转换成光信号，再透过光纤将光信号进行传递，属于有线通信的一种。

光经过调变后便能携带资讯。

光纤通信利用了全反射原理，即当光的注入角满足一定的条件时，光便能在光纤内形成全反射，从而达到长距离传输的目的。

1－2、光纤通信技术有哪些特点？参考答案：(1)无串音干扰，保密性好。

(2)频带极宽，通信容量大。

(3)抗电磁干扰能力强。

(4)损耗低，中继距离长。

(5)光纤径细、重量轻、柔软、易于铺设。

除以上特点之外，还有光纤的原材料资源丰富，成本低;温度稳定性好、寿命长等特点。

1－3、光纤通信系统由哪几部分组成？简述各部分作用。

参考答案：光纤通信系统最基本由光发送机、光接收机、光纤线路、中继器以及无源器件组成。

其中光发送机负责将信号转变成适合于在光纤上传输的光信号，光纤线路负责传输信号，而光接收机负责接收光信号，并从中提取信息，然后转变成电信号，最后得到对应的话音、图象、数据等信息。

(1)光发送机：由光源、驱动器和调制器组成，实现电/光转换的光端机。

其功能是将来自于电端机的电信号对光源发出的光波进行调制，成为已调光波，然后再将已调的光信号耦合到光纤或光缆去传输。

(2)光接收机：由光检测器和光放大器组成，实现光/电转换的光端机。

其功能是将光纤或光缆传输来的光信号，经光检测器转变为电信号，然后，再将这微弱的电信号经放大电路放大到足够的电平，送到接收端的电端机去。

(3)光纤线路：其功能是将发信端发出的已调光信号，经过光纤或光缆的远距离传输后，耦合到收信端的光检测器上去，完成传送信息任务。

(4)中继器：由光检测器、光源和判决再生电路组成。

它的作用有两个：一个是补偿光信号在光纤中传输时受到的衰减;另一个是对波形失真的脉冲进行整形。

(5)无源器件：包括光纤连接器、耦合器等，完成光纤间的连接、光纤与光端机的连接及耦合。

英语关于科技的作文250字左右全文共6篇示例，供读者参考篇1Technology is Awesome!Technology is so cool! I love all the gadgets and gizmos that make our lives easier and more fun. My favorite piece of technology is definitely my tablet. I use it for playing games, watching videos, and even doing my homework sometimes. It's like having a little portable computer that can do almost anything.Another really neat technology is virtual reality headsets. With VR, you can be transported to amazing digital worlds and play incredibly immersive games. It's like you're really there! I went to a friend's house last weekend and we played a VR game where we had to fight off zombies. It felt so real, I actually got scared a few times!Robots are also mind-blowingly awesome tech. They can do chores, assemble cars, and even perform surgeries. How crazy is that? I saw a robot at the science museum that could solve aRubik's cube in just a few seconds. I don't think I could ever do that!Technology is advancing so quickly, who knows what amazing inventions are coming next? Maybe flying cars, holograms, or even teleportation! I can't wait to see what the future holds. In my opinion, the more tech the better! It just makes everything more efficient and fun.篇2科技带给我们的乐趣嗨，大家好！我是小明，今天我要和大家聊一聊科技给我们带来的乐趣。

全文分为作者个人简介和正文两个部分：作者个人简介：Hello everyone, I am an author dedicated to creating and sharing high-quality document templates. In this era of information overload, accurate and efficient communication has become especially important. I firmly believe that good communication can build bridges between people, playing an indispensable role in academia, career, and daily life. Therefore, I decided to invest my knowledge and skills into creating valuable documents to help people find inspiration and direction when needed.正文：日常生活交通工具英语作文初二全文共3篇示例，供读者参考篇1Daily Transportation: Getting Around in My WorldAs a middle school student, my daily life involves a lot of moving around. Between going to classes, extracurricular activities, hanging out with friends, and running errands, I'mconstantly on the go. The modes of transportation I use play a huge role in my lifestyle and routine. Let me tell you about the various ways I get from place to place each day.Of course, walking is one of the most common ways I get around, especially for short distances. My school isn't too far from my house, so I often walk there in the mornings. It's about a 15-minute walk through my neighborhood. I really enjoy these morning walks as they allow me to wake up, get some fresh air and exercise before sitting in a classroom all day. After school, I'll sometimes walk home as well if I don't have other activities or commitments. Walking is free, environmentally friendly, and good exercise.For longer distances where walking isn't practical, I rely on my bicycle quite a bit. I got a new mountain bike for my birthday last year and I love it! It's perfect for riding around my neighborhood and town. I'll cycle to the local park, library, or my friends' houses pretty often after school and on weekends. My bike gives me a sense of freedom and independence to go where I want, when I want. I make sure to wear my helmet and follow all the rules of the road for cyclists' safety. Biking has been a fun way for me to stay active too.When I need to get somewhere quite far, like my dance classes across town or my grandmother's house in the next city over, my parents will usually drive me. We have a minivan that fits my whole family comfortably. I don't mind being driven places by my parents, but I do look forward to being able to drive myself once I'm old enough. For now though, I'm just grateful they can chauffeur me around! In the car, I'll listen to music, do homework, or just look out the window at the scenery. Long car rides can be a nice chance to rest and recharge between activities.Public transportation has also become a part of my routine recently. Last summer, I attended a coding camp at the local college, which was too far away for biking or walking. My parents showed me how to take the public bus system to get there. I felt so grown up taking the bus by myself! Of course, I had to carefully plan my route and leave extra time, but I enjoyed the independence. The city buses were also helpful when I went to the movies or mall with my friends rather than asking my parents for rides. Utilizing buses, trains, or subways makes me feel like a real adult navigating the world.For bigger trips and vacations, air travel is obviously required. My family flew to Florida last spring break to visit my aunts andgo to Disney World. While plane travel is definitely the fastest way to get somewhere far away, I find it's also the most stressful with having to arrive very early, get through security, and obey all the rules about what you can bring. Still, watching movies, eating snacks, and looking out the window at the clouds and landscape below made the flights fairly enjoyable. It's an efficient way to travel long distances when time is limited.Ride shares and taxis are another option I've utilized from time to time. If my parents are both at work and I need an emergency ride somewhere, they'll order an Uber or Lyft for me so I'm not stranded. My friends and I have also split the cost of a taxi when going somewhere after school events before. Ride shares are convenient when public transportation isn't running or convenient for the route needed. However, they can get quite expensive compared to free options like walking or biking.Of course, transportation isn't an isolated part of my life - it directly impacts my daily activities and lifestyle. How I choose to get around affects my overall schedule, budget, exercise, environmental impact, and more. Getting places efficiently and safely is crucial but I also aim to make sustainable choices for my health and the planet when I can. Using methods like walking,biking, or public transit helps reduce my carbon footprint compared to driving frequently.On the other hand, the different transportation options available to me enable me to live an active, social lifestyle. If I was limited to only walking short distances, I wouldn't be able to easily attend all my activities, see friends, or go certain places for fun. Having transportation diversity gives me independence and freedom. Although driving myself will open up even more possibilities, I'm grateful for the various modes I can currently use as a middle schooler to stay on the move each day!篇2My Daily Transportation AdventuresAs a busy middle school student, getting around each day is definitely an adventure! Between classes, extracurricular activities, hanging out with friends, and running errands for my family, I feel like I spend half my life just trying to get from one place to another. But you know what? I actually really enjoy the transportation part of my routine. It gives me a chance to clear my mind, listen to music, and sometimes just zone out and relax for a bit between my many obligations.Of course, my main mode of transport is the classic bicycle. I've been riding a bike for as long as I can remember, and I have to say, it's still one of my favorite ways to get around the neighborhood. There's just something so freeing about pedaling along, feeling the wind in your face, and working those leg muscles. Plus, it's environmentally friendly and cheaper than taking a bus or getting rides from my parents all the time. My bike and I have been through a lot together - muddy trails, epic crashes, you name it. I've learned all the shortcuts and back roads to get anywhere I need to go efficiently.That said, biking does have its limitations, especially when I need to travel longer distances. That's when I have to fall back on public transportation. I'm lucky that my city has a pretty good bus system that can get me just about anywhere I need to go. Sure, the buses can be crowded and smelly sometimes, and you always run the risk of getting stuck next to a weirdo, but overall it beats having to ask my parents for rides constantly. The buses run regularly enough that I can usually just show up and wait for the next one. My friends and I have setbus stop meetup spots where we'll often hang out until our chariots arrive.And then there are those glorious occasions when my parents actually do offer me a ride somewhere. Getting droppedoff by mom or dad might not be the height of cool, but I have to admit there's nothing quite like the comfort and convenience of hitching a ride in the family vehicle. No timetables, no crowding, no wondering if I'll make it on time - just sitting back and getting chauffeured directly to my destination. Extremely underrated mode of transport if you ask me. My parents have started using those ride share apps more too, which is handy for when nobody's available to play designated driver.My friends' parents also get roped into the teenage transportation game quite a bit. Coordinating rides with everyone's schedules can be a nightmare, but we've managed to establish some solid carpool circles. Having teens pile into your minivan to get ferried all over the place is basically a rite of passage for parents in our community. I have to hand it to the poor adults who end up as our de facto chauffeurs - dealing with herds of rowdy kids packed into their vehicles can't be easy. But they're the real MVPs making it possible for us to get to all our activities without riding the bus everywhere.Of course, no discussion of teenage transportation would be complete without mentioning walking. Yeah, I know it's not the most efficient way to get around, but sometimes you just have to embrace the simplicity of feet hitting pavement. When theweather is nice, walking can be legitimately enjoyable, giving you a chance to soak in your surroundings and maybe even discover new spots around town. My buddies and I will often set out on long, aimless walks together, going nowhere in particular. Just feeling free and easy, strolling along at our own pace. These walks have been the setting for many great conversations and unforgettable memories over the years.I'd be lying if I said I never wished I could just hop in a car myself and take off whenever I wanted -ævery teenager dreams of that independence. But for now, I'm actually pretty content being a pedestrian, cyclist, and backseat driver. Using all these different transportation methods to navigate my daily life keeps things interesting and gives me a chance to slow down and appreciate the journey, not just the destination. Who knows, by the time I'm an adult, they'll probably have teleportation figuredout or something. But for these middle school years, I'm happy to take the long way, mixing it up between my trusty bike, bumpy buses, annoying siblings in the car, and good oldån' walks with friends. It's all part of the transportation adventure that is my daily life.篇3Modes of Transportation in Our Daily LivesTransportation plays a vital role in our daily routines, enabling us to navigate through the bustling streets and reach our desired destinations. As a middle school student, I have experienced various modes of transportation, each with its unique characteristics and advantages. In this essay, I will delve into the different means of commuting and share my personal experiences and observations.Walking: The Simplest yet Profound Way to Get AroundWalking is perhaps the most fundamental and environmentally friendly mode of transportation. It requires no fuel, no machinery, and no complicated technology – just the power of our own two feet. For short distances, walking is not only convenient but also provides numerous health benefits. It promotes physical activity, reduces stress levels, and allows us to connect with our surroundings in a more intimate way.I particularly enjoy walking to and from school whenever the weather permits. It's a refreshing start to my day, allowing me to breathe in the crisp morning air and clear my mind before diving into the day's academic responsibilities. The gentle exercise also helps me stay energized and focused throughout the school hours.Cycling: An Eco-Friendly and Exhilarating Way to CommuteCycling is another environmentally conscious mode of transportation that has gained popularity among individuals of all ages. It combines the benefits of physical exercise with the convenience of faster travel compared to walking. Cycling not only reduces our carbon footprint but also promotes a healthier lifestyle and can be an invigorating experience.In my neighborhood, I often see fellow students cycling to school, their backpacks securely strapped to their bikes. The sight of them zipping past, their helmets securely fastened, always fills me with a sense of admiration and a desire to join them on their two-wheeled adventures.Public Transportation: Efficient and Accessible for AllPublic transportation systems, such as buses and trains, play a crucial role in urban mobility. They offer a convenient and affordable way for individuals to commute, reducing traffic congestion and contributing to a more sustainable environment.My city's bus system is a lifeline for many students, including myself. It's a reliable mode of transportation that allows us to reach our destinations without the hassle of navigating through heavy traffic or finding parking spots. The bus routes arewell-planned, connecting various neighborhoods and ensuringthat students from diverse areas have access to educational institutions.Personal Vehicles: Convenience at a CostWhile personal vehicles, such as cars and motorcycles, offer unparalleled convenience and flexibility, they also come with environmental and financial consequences. Owning and operating a personal vehicle requires a significant investment in fuel, maintenance, and insurance costs.In my family, we rely on our trusty car for longer journeys or when carrying heavier loads. However, for shorter distances within our neighborhood, we often opt for more eco-friendly alternatives, such as walking or cycling. It's a conscious effort to reduce our carbon footprint and contribute to a greener future.The Future of Transportation: Embracing Innovation and SustainabilityAs technology continues to evolve, the transportation landscape is also undergoing transformative changes. Electric vehicles, ride-sharing services, and even self-driving cars are becoming more prevalent, offering innovative solutions to our commuting needs while prioritizing sustainability.I'm fascinated by the prospect of self-driving cars and how they could revolutionize the way we travel. Imagine being able to complete homework assignments or catch up on reading while the car navigates through traffic autonomously. It's an exciting concept that could potentially reduce accidents caused by human error and alleviate traffic congestion.ConclusionIn conclusion, transportation plays a pivotal role in our daily lives, shaping our experiences and enabling us to navigate through the world around us. From the simplicity of walking to the efficiency of public transportation and the convenience of personal vehicles, each mode offers unique advantages and challenges.As we look towards the future, it's crucial to embrace innovative and sustainable transportation solutions that prioritize both convenience and environmental responsibility. By making conscious choices about how we commute, we can contribute to a greener and more sustainable world for generations to come.。

七年级下册外研版英语英语作文未来学校生活全文共6篇示例，供读者参考篇1My Future School Life: A Glimpse into Tomorrow's ClassroomsImagine waking up one morning and everything around you has magically transformed into a futuristic wonderland. The alarm buzzing on your smartwatch isn't an obnoxious blaring noise, but a gentle vibration synced with soothing nature sounds. You hop out of bed, and your smart mirror greets you with a friendly "Good morning!" before displaying the day's weather forecast and a personalized daily schedule.As you get ready for school, you remember the virtual reality field trip your science class is taking today. How awesome is that? No more stuffy buses or cramped auditoriums – just slipping on a VR headset and being transported to the depths of the Amazon rainforest or the surface of Mars! You can almost smell the exotic flora and feel the Martian dust swirling around you.The school day begins with an automated drone delivering your textbooks and supplies right to your desk. No more luggingaround that heavy backpack! The books are all digitized too, so they instantly update with the latest information. You can highlight, annotate, and cross-reference with just a few taps on the screen.Your first class is Coding 101 – a requirement for all students now that technology governs virtually every aspect of our lives. But this isn't your typical boring lecture. You slip on augmented reality glasses that project a vibrant 3D coding environment all around you. Line by line, you build and manipulate software programs with simple hand gestures. It's like living inside the Matrix!Next up is Literature Appreciation, but there are no musty old books to lug around. You just don some lightweight smart lenses that overlay the prose with stunning visuals as the narrator's voice reads aloud. The words seem to dance right off the page in vivid detail.For gym class, you visit the school's holographic sports arena – a massive dome that can simulate any athletic environment imaginable. Today it's an Olympic-sized pool for swim practice. Underwater sensors provide instant feedback on your stroke technique, while a buoyant virtual coach demonstrates the proper form. Then with just a voice command, the dome morphsinto a rock climbing crevasse with adjustable handholds and slopes.What's for lunch, you ask? Your cafeteria tray folds out into a high-tech flatscreen, where you can scroll through a menu of nutritious meal options. With a tap, your selected dish materializes before you via 3D food printing technology. The printers can synthesize any ingredients from basic compounds like water, proteins, and vitamins – no more wilted salads or expired milk!The afternoon is reserved for passion projects based on each student's unique interests and learning styles. Feeling artistic? Step into the immersive studio and sculpt a masterpiece with haptic gloves that simulate different materials like clay or paint. More of a music buff? Compose a symphony by plucking melodies from the air with motion-tracking sensors. Or you can dive into programming your own video game, with the code materializing around you as living, breathing worlds.As the final bell rings, you linger behind to chat with friends via holographic video uplinks. People used to just stare at tiny phone screens, but holographic calls make it feel like your BFFs are right there with you! You can even take some crazy groupselfies, posing alongside 3D avatars and whacky augmented reality accessories.What an amazing day of learning and fun! And to think, this is just a normal day at school in the not-so-distant future. Our great-grandparents could have never imagined anything like it. I can't wait to see what other mind-blowing technologies are in store. I mean, what if we could take actual teleportation field trips instead of just VR? Or have nanobot tutors that can instantly upload knowledge into our brains?The possibilities are endless. The future of education is here, and it's blowing my mind! I feel so lucky to be a kid in this brave new world of boundless exploration and discovery. Learning has never been this wild, immersive, and hands-on. I'm endlessly inspired to dream big and embrace the unknown. Tomorrow can't come soon enough!篇2My Dream School of the FutureHey there! I'm a 7th grader and today I want to share my vision for the ideal school of the future. As a kid who loves learning but also really values fun and freedom, I've put a lot ofthought into what my dream school would be like. Trust me, it's going to be awesome!First off, the buildings and campus will be super modern and high-tech. We're talking sleek designs with huge windows that let in tons of natural light. The classrooms will have adjustable, comfy seating instead of those hard, old-fashioned desks we have now. And the latest computers, tablets, and virtual reality gear will be readily available for lessons and projects. No more outdated, boring textbooks - we'll have interactive digital coursework that makes learning come alive!But wait, there's more! My dream school will be really environmentally-friendly. The whole campus will run on renewable energy like solar and wind power. There will be vertical gardens on the walls to grow fruits and veggies for our healthy cafeteria meals. Recycling and composting will be a huge priority. We'll use sustainable materials and practice zero-waste policies everywhere. Being eco-conscious will be a core value woven into everything we do.The classes and curriculum are where it really gets exciting though. Instead of having to sit through lectures all day, we'll have a balanced mix of hands-on activities, group projects, field trips, and independent research. Learning by doing andexploring real-world applications - that's the way to make knowledge stick! We can use augmented reality to visualize abstract concepts. And if we need extra help, AI tutors will be available virtually 24/7.For example, in science class we might spend a few weeks learning about renewable energy by building and testing model wind turbines and solar panels. Then we'd go on a field trip to an actual solar farm to see the technology in action. Back at school, we could analyze data we collected and propose ideas for improving the efficiency using cutting-edge simulation software. So much better than just reading about it in a textbook, right?The school schedule will be customized too. Since not everyone learns best at the same times, we'll have flexible start times in the morning. And the daily schedule will alternate between core academics and enrichment activities like arts, music, coding, entrepreneurship, you name it. We can dive into our passions and try new pursuits based on our unique interests and strengths.Recess and breaks will be crucial for recharging, but not like today's boring playgrounds. My dream school will have epic spaces for physical activities and fun hangouts. I'm talking climbing walls, indoor trampoline parks, holograms forinteractive gaming, cozy reading nooks, and creativity zones for art and making. Outdoors there will be beautiful green spaces like gardens, trails, and maybe even a lake for kayaking and canoeing. So many amazing ways to stay active, socialize, and blow off steam!Now you might be wondering - won't this amazing place cost a ton of money? Well, my dream school will be tuition-free and open to all students. It will be funded by the government, private donors, and partnerships with companies that want to invest in developing bright young minds. Resources will be allocated super efficiently using advanced data analytics. With all this support, every child can have access to a top-notch,future-focused education.You're probably also curious how we'll make sure everyone feels safe, respected, and included in this modern wonderland. Bullying and discrimination will have zero tolerance - end of story. We'll learn about diversity, empathy and conflict resolution starting at a young age. Counselors will be available along with positive discipline policies that prioritize accountability, restoration and learning. The whole community will uplift core values like integrity, kindness and teamwork.Last but not least, teachers at my dream school will bereal-life superheroes! They'll get excellent training incutting-edge teaching methods, technology, social-emotional skills, you name it. Their compensation and benefits will be excellent to attract the best and brightest educators. And their roles will be about guiding and mentoring students to discover their own篇3The School of the Future: A Student's DreamHi there! My name is Jamie, and I'm an 8th-grade student. Today, I want to share with you my vision of what school will be like in the future. Get ready, because it's going to be awesome!First of all, say goodbye to those boring, old-fashioned classrooms with rows of desks and chalkboards. In the future, our classrooms will be like something out of a sci-fi movie! Imagine walking into a room with holographic displays, interactive whiteboards, and even virtual reality stations. We'll be able to explore ancient civilizations, dive into the depths of the ocean, or even travel through the solar system – all without leaving our seats!But that's not all. Our lessons will be personalized to our individual learning styles and interests. No more one-size-fits-all approach! With the help of advanced AI systems, our teachers will be able to tailor the curriculum and teaching methods to suit each student's needs. Struggling with math? No problem! The AI will identify your weaknesses and provide customized exercises and explanations to help you understand the concepts better.Speaking of teachers, they won't just be lecturing at the front of the class anymore. They'll be more like mentors and guides, helping us navigate the world of knowledge and encouraging us to think critically and creatively. We'll work on projects in small groups, collaborating with classmates from around the world using virtual meeting spaces.And forget about those heavy backpacks full of textbooks –everything will be digital! We'll have lightweight tablets or maybe even some kind of futuristic glasses that can display information right before our eyes. No more lugging around a ton of books or worrying about forgetting them at home.But it's not all about technology, of course. Our future schools will also prioritize students' mental and physical wellbeing. There will be designated spaces for meditation, yoga, and mindfulness activities to help us destress and recharge. Andforget about those boring school lunches – the cafeteria will offer a variety of healthy, delicious options prepared by professional chefs, using fresh, locally-sourced ingredients.And let's not forget about extracurricular activities. In the future, we'll have access to all sorts of amazing clubs and programs, from robotics and coding to environmental activism and creative writing. There will be opportunities to explore our passions, develop new skills, and connect with like-minded students from around the globe.Now, I know what you're thinking: "Jamie, this all sounds like a dream! How could any of this be possible?" Well, my friends, the future is closer than you think. With the rapid advances in technology, coupled with a growing emphasis onstudent-centered learning and holistic development, the school I've described may very well become a reality sooner than you expect.So, get ready to say goodbye to the dusty chalkboards and outdated textbooks of the past. The future of education is bright, and it's going to be an incredibly exciting journey. I can't wait to be a part of it!篇4Future School LifeWow, can you imagine what school will be like in the future?I sure can, and let me tell you, it's going to be amazing! As a seventh-grader, I can't help but dream about the incredible advancements that will shape our education system in the years to come. Prepare to be blown away!First and foremost, we'll say goodbye to those clunky, outdated textbooks that weigh a ton and give us backaches. In the future, we'll have sleek, lightweight tablets or even holographic displays that will provide us with all the information we need. No more lugging around a backpack full of heavy books – everything will be accessible with just a few taps or voice commands.But it's not just about the technology; the way we learn is going to change too. Goodbye, boring lectures and monotonous classes! In the future, classes will be interactive, engaging, and tailored to each student's individual learning style. Imagine virtual reality simulations that transport us to different historical periods or distant planets, allowing us to truly immerse ourselves in the subject matter. Or how about holographic teachers who can break down complex concepts into easy-to-understand visuals right before our eyes?Speaking of teachers, they won't just be imparters of knowledge but more like mentors and guides. With the help of advanced artificial intelligence (AI) systems, they'll be able to track our progress, identify our strengths and weaknesses, and provide personalized support to help us reach our full potential. No more one-size-fits-all approach!And let's not forget about the school facilities themselves. Gone will be the days of drab, uninspiring classrooms. Our future schools will be architectural masterpieces, with spacious,open-concept learning spaces that encourage collaboration and creativity. Imagine walls that double as interactive whiteboards, or outdoor classrooms that seamlessly blend nature and technology. It'll be like something straight out of a science fiction movie!But it's not all about academics – our future schools will also prioritize our overall well-being. Mindfulness and meditation rooms will help us destress and recharge, while state-of-the-art fitness centers and healthy cafeterias will promote an active and balanced lifestyle. After all, a sound mind and body are essential for learning.And let's not forget about the social aspect of school life. In the future, we'll be able to connect with students from all aroundthe world through virtual exchange programs and collaborative projects. Imagine working on a science experiment with a classmate from Tokyo or learning about different cultures from a friend in Brazil – the possibilities are endless!As excited as I am about the future of education, I can't help but feel a little nostalgic thinking about the good old days. I'll miss the simple pleasures of sharpening pencils, flipping through the pages of a worn-out textbook, or scribbling notes in the margins. But hey, progress is progress, and I can't wait to see what the future holds for us students.So, buckle up, fellow classmates! The future of school life is going to be an incredible ride, filled with endless possibilities and mind-blowing innovations. Who knows, maybe one day we'll even have teleportation devices that'll take us straight to class (no more excuses for being late!). Whatever comes our way, one thing's for sure: learning has never been this exciting!篇5My Dream School of the FutureHi there! My name is Alex and I'm a 7th grader. Today, I want to tell you all about my dream school of the future. It's going to be so awesome and high-tech, with all sorts of amazing thingsthat will make learning fun and easy. Put on your imagination hats, because we're going on an adventure into the classroom of tomorrow!First up, no more boring old textbooks or notebooks. At my future school, we'll have these cool digital tablets that can display any book or worksheet we need with just a tap. The tablets will even read the pages out loud if we want, with different voice options to keep things interesting. No more hurting our backs lugging heavy books around either!But that's not all these future tablets can do. They'll have built-in translators so we can read things in any language. If there's something I don't understand, I can just highlight it and the tablet will give me simple explanations. It can solve math problems step-by-step too. How awesome is that?Our classrooms will be super modern and teched-out as well. The desks will be adjustable standing desks to keep us active and focused. The walls will be huge interactive whiteboards where our teachers can display multimedia lessons. Maybe there will even be hologram projectors so we can see 3D models of whatever we're learning about!Speaking of teachers, they'll have it made in the future too. No more grading papersuntil late at night. AI assistants will beable to grade most of our work automatically and give us feedback. The teachers can focus on the actual teaching instead of getting buried under piles of homework to grade.When it's time for P.E., the gym will be outfitted with virtual reality workout stations. We can run through digital forests, climb virtual mountain ranges, or play any sport in amazingly realistic environments. No childhood will be consumed by boring treadmills ever again!The cafeteria will be super sustainable with vertical farms growing fruits and veggies on-site. The food will be deliciously nutritious and there won't be any waste because it's all grown right there. For beverages, we'll have awesome robot baristas that can whip up any drink combination we can dream of.Outside, we'll have high-tech playground equipment like jet pack swings and anti-gravity jump balls. The sandbox will be able to shape-shift into any landscape we want—beaches, canyons, you name it! There will be plenty of shaded solar groves for outdoor classes too. No more getting sweaty in the hot sun.That's just a small taste of what my dream future school will be like. With technologies like AI, VR, vertical farming, and more, going to school will be an absolute blast. I'll be learning whilehaving adventures inside immersive digital worlds or experimenting with a zillion fantastic tools.The best part is, a lot of this future tech already exists in some form today. With how quickly things are advancing, who knows how amazingly awesome schools will be just a few years from now? Maybe some of you reading this will be designing the classroom of the future when you grow up. I sure hope so, because that future can't come soon enough for me!Well, I've gone on long enough. What does your dream school look like? Maybe it will have teleporters for getting to class on time or a room where you can learn anything just by downloading it into your brain. A kid can dream, right? I just know that however unbelievable the future ends up being, it's going to be a million times better than the old-fashioned chalkboard and textbook days. The future of learning is looking brighter than ever before!篇6My Dream School of the FutureHi there! My name is Alex, and I'm a seventh-grader at Greenfield Middle School. I know I'm still pretty young, but I've been thinking a lot about what school might be like in the future.It's crazy to imagine all the changes that could happen in the coming years! Let me tell you about my dream school of the future.First off, I really hope that in the future, we won't have to carry heavy backpacks filled with books anymore. Imagine having all your textbooks, notebooks, and study materials on a single tablet or laptop! It would be so much easier on our backs and shoulders. Plus, we could easily access all our notes and assignments from anywhere, anytime.Speaking of technology, I can't wait for classrooms to be fully equipped with the latest gadgets and gizmos. I'm talking about interactive whiteboards, virtual reality headsets, and even robots that can assist teachers! Learning would be so much more engaging and fun. We could explore different historical periods or travel to distant galaxies without ever leaving our seats!But it's not just about technology. I also dream of a school where we have more hands-on learning experiences. Instead of just reading about science experiments, we could actually conduct them in state-of-the-art labs. And for subjects like art or woodworking, we'd have access to all the tools and materials we need to create awesome projects.Now, let's talk about the school building itself. Imagine a modern, eco-friendly structure with plenty of natural light, green spaces, and energy-efficient systems. We could have solar panels on the roof and a rainwater harvesting system to reduce our environmental impact. And instead of dull, boring classrooms, we'd have flexible learning spaces that can be easily rearranged for different activities.But it's not just about the physical aspects of the school. I also hope that in the future, we'll have more personalized learning experiences. With the help of advanced algorithms and AI, our lessons could be tailored to our individual strengths, weaknesses, and learning styles. No more one-size-fits-all approach!And let's not forget about extracurricular activities. In my dream school, we'd have a huge range of clubs and organizations to choose from, catering to every interest imaginable. Whether you're into robotics, music, theater, or even coding, there would be something for everyone.But it's not just about the teachers – I also dream of a school where students from all backgrounds and cultures can come together and learn from each other. We'd have exchange programs and virtual classrooms that connect us with studentsfrom around the world, broadening our perspectives and fostering understanding and respect.Now, I know all of this might sound a bit far-fetched, but hey, a kid can dream, right? Who knows what the future holds? With the rapid pace of technological advancement and ourever-evolving understanding of how people learn best, anything is possible!One thing's for sure, though – school in the future won't be boring or old-fashioned. It'll be an exciting, dynamic place where we can truly explore our passions, develop our skills, and prepare for the challenges and opportunities that lie ahead.So, what do you think? Are you as excited as I am about the possibilities? I can't wait to see what the future holds for education. Who knows, maybe some of you reading this will be the ones shaping the schools of tomorrow!。