01Introduction
国际商务函电第一章Unit01 Introduction to Business Letters
Criteria for Business Letters
F. CONCRETENESS Our writing should be vivid, specific and definite.
Unit One Introduction to Business Letters (商务信函概论)
The General Procedures for Business Letter Writing:
e.g. We have received with many thanks your letter of 20 May, and we take the pleasure of sending you our latest catalog. We wish to draw your attention to a special offer which we have made in it.
Unit One Introduction to Business Letters (商务信函概论)
Example of the Formats of a Letterhead:
EASTERN TEXTILES IMP. & EXP. CO.,LTD. 34297 Shangcheng Road, Shanghai, China Tel: 6606811 Fax: 6507631 E-mail: bcxbcx@
Unit One Introduction to Business Letters (商务信函概论)
何 昌 个人邮箱：hechang171@ 教学邮箱： hechangjx@(3816875)
Unit One Introduction to Business Letters (商务信函概论)
英语介绍泉州
2
History
History
Quanzhou has a history dating back over 1700 years. It was founded in the year 260 and has since become an important port city in Chinese history. During the Tang Dynasty, Quanzhou became a major international port
ancient history with modern development. Whether you are interested in history, culture, or just enjoying a vacation on
the beach, Quanzhou has something to offer everyone
its literature, with many famous writers and poets having lived or worked here. In addition, Quanzhou is home to a variety of traditional crafts, such as embroidery, paper-cutting, and陶瓷 (ceramics)
Quanzhou, located on the southeast coast of Fujian Province, is a city with a long history and rich cultural and historical heritage. It is famous for its ancient city, beautiful scenery, and delicious food. In this article, we will introduce Quanzhou from several aspects, including its history, culture, tourism, and food
少儿英语启蒙 英语游戏 lesson plan01-introduction 超详细教学步骤内容
Lesson 01Intro Lesson (Ages 3-7) General：Age: 3-7 years Time: 40 mins - 1 hourObjectives: Greetings, names, follow simple instructions, identify and recognize 3 colorsStructures: "Hello", "What's your name", "My name is...", "Goodbye", "Give me..."Target Vocab: red, blue, green, flower, stand up, sit down, hands up, hands down,jump, run, turn around, pass, touchYou will also need:•name tags for each student• a glove puppet• a small ball•crayons• 3 sheets of origami colored paper (red, green, blue)• 3 balloons (red, blue, green)•cushions (1 per student)•CD / Tape player / PC / Something to play the Hello and Goodbye songs on Your students will need:•colored crayons (or pencils)Lesson Procedure:Greetings Warm Up and Maintenance:1. GreetingsGreet the students by name as they enter the classroom and gesture for them to sit down. It's a good idea to have a cushion for each student (and parent if also taking part) as this makes sitting arrangements easy to organize. Try and arrange the cushions beforehand spaced out in a fan-shape around you.2. Name TagsName Tags Before class prepare some name tags (stickers or pin-on tags) with each student's name written on in lower case letters. Sit down with your students and lay out the name tags in front of you. Pick up each tag and call out the name. Try and encourage each student to put their hand up and say "yes". Hand over the tags andhelp to pin / stick on.In later lessons, once your students can recognize their written name, you can have them pick out their own name tags.New Learning and Practice:1.Play "Ball Pass" and say namesTake a soft ball and pass it to your nearest student, saying "Pass". Have each student pass the ball around the circle. Next, hold the ball and say your name. Have each student say their name as they pass the ball to each other. Make sure they pass, not throw, roll, etc. If a student doesn't pass make sure s/he does it again until done properly.2.Introduce glove puppet - greetings and introductions activityYour students will love this. Get hold of a glove puppet (I use Cookie Monster bought from Toys 'R' Us) and put it in a bag before class. Bring out the bag, open it enough to see in and shout into the bag "Hello!". Then move your ear to the opening to listen - nothing. Go to each student and encourage them to shout "Hello" into the bag - each time nothing happens. Finally, get all the students together to shout "Hello!" at the same time. This time the puppet wakes up and jumps out of the bag! Then model the role play with the puppet:Introduce glove puppet - greetings and introductions activity Teacher:"Hello", What's your name?"Puppet:"My name is...".Then move onto the first student and say "Hello". Encourage him/her to say hello back. Let the students touch, cuddle and stroke the puppet. My puppet also likes to nibble their feet and arms. Next, the puppet asks each student: "What's your name?". If they are old enough try and encourage "My name is..." but for the really little ones (3 and under) just saying their name is fine. Finally, go around saying "Goodbye" and "See you" before going back into the bag and back to sleep.3.Sing the "Hello Song"Sing the "Hello Song" Sit in a circle and listen to the song (clap along or pat knees). Play it once more emphasizing "Hello". Your students will pick up the words surprisingly quickly.Alternatively, you can sing the "Hello, Hello" song following the tune of Frere Jacques: Hello, hello, Hello, hello,How are you? How are you?I'm fine, thank you, I'm fine, thank you,We're ok, We're ok.Lyrics for "The Hello Song"Hello, hello,How are you today?Hello, hello,How are you today?I’m fine, thank you,I’m fine, thank you,I’m fine, thank you,And how about you?Hello, hello,How are you today?I’m fine, thank you,And how about you?Gestures for "The Hello Song"These are quite straight forward. First time you play the song do the gestures and encourage everyone to do them with you.Wave as you sing the "Hello, hello" parts.Gesture to others as you sing "How are you today?"Point to yourself as you sing "I’m fine, thank you"Hand gesture towards another student as you sing "And how about you?".4. Do "Exercise Routine" activityTime for some action. Say the following and have the students follow your lead:Do "Exercise Routine" activity" Stand up (T stands and so does everyone else) "Hands up / hands down" (do 4 or 5 times)"Jump" (4 or 5 times)"Run! / Stop!" (4 or 5 times)"Turn around! / Stop!" (4 or 5 times)finally "Sit down".5. Name writing practiceIn this lesson your students are going to practice writing their names. For really young ones, this may be their first time to do so - don't worry if their first effort is a scrawly mess - always encourage and praise.You will need to prepare a writing sheet for each student before class with their name written in dots for them to practice tracing their names .Prepare the sheets something like this:6. Do the Name Flower Craft activityDo the Name Flower Craft activityNow that everyone has had a chance to practice writing their name you can do the name craft activity.Before class print out the "Name Flower Craft" sheet and copy / cut out the flower shapes so that there are enough to give one to each student (do a few extra in case of emergencies!).Get each student to write their name on the line and then color in their flower. Students can now decorate the classroom by sticking their name flowers on the walls. Alternatively, have students make a name poster by sticking all of the name flowers onto one large piece of construction paper (I like to make a tree shape out of brown card for students to stick their flowers on).7.Teach Colors: red, blue, greenTeach Colors: red, blue, greenA great lesson to follow this one is the "Colors Lesson" (you can download it for free at our website). In this lesson you can start by teaching the first 3 colors (red, blue and green) and then in the next class you can continue with the other colors (yellow, pink, purple, orange).Origami paper is great for this, or just some colored paper/card cut into squares. Sit everyone in a circle and hold up the first colored paper and elicit the color (e.g. red). Chorus and practice saying the color. Do this for the rest of the colors.8.Play "Color Pass", "Color Touch" and "Color Hold Up"Play "Color Pass", "Color Touch" and "Color Hold Up"Now take each color and pass it to your nearest student. Say "red" as you pass red, etc. The students pass the colors round the circle. Next, lay the 3 colors in the middle of the circle. Say "Hands up". Students raise their hands. Then say "Touch.....red!" and the students should all try and touch the red colored paper. Do for all of the colors. Finally, give each student one of the colored papers. Say "Hold up....blue!" - the students holding the blue papers raise them into the air.NOTE: for these games you'll probably have to give lots of help and encouragement. For example, if one of your students doesn't hold up the colored paper when asked look at him/her and gesture what to do. If their mothers are with them have them help.9.Play "Find the Color"Now get each student to give you back their colored paper by saying "Give me (blue)". Collect all the colors. Then place the colored papers on the floor around the room. First model by saying "Touch blue". Then stand up, go to a blue paper, touch it and say "blue" and go back to your place. Now say to one student "(Miki), touch green" and that student should stand up, find the correct color and touch it. Get everyone to have at least one go. Finally, get students to stand up and give you back the colors as you say them (e.g. Paulo, give me red").10.Play "Balloon Kick"You need three balloons - a red, a blue and a green one. Take one balloon and elicit the color. Then chorus "(blue) balloon" x3. Now blow up the balloon (little kids love watching this) and tie the end. Pat the balloon to one student and encourage him/her to say its color as they catch it. Let the student pat it back to you and repeat the color with all students. Then do the same for the other 2 balloons. Finally, line the balloons up, have the students stand up and model the activity: "Ok, (your name) kick the (blue) balloon!", then run up to the (blue) balloon and kick it. Now instruct one student to kick a balloon, give loads of help and encouragement and then do with all the other students.Wrap Up:1.Assign Homework: "Color the Balloons"Hold up the homework worksheet and model coloring in the 3 balloon pictures (in red, blue and green). Elicit each color as you go. Give out the worksheets and say "Put your homework in your bags" and help them to do so - this is important as they will probablywant to start coloring them right away.2. Say Goodbye to glove puppetSay Goodbye to glove puppetTake out the bag again and get everyone to wake up the glove puppet by shouting its name into the bag (e.g. "Cookie Monster!"). Bring out the puppet and go through the same routine - go to each student and say hello, ask their name and the say goodbye / see you. Then put the puppet back in the bag (back to sleep).3.Sing "Goodbye Song"The "Goodbye Song" is a great way to sign off the class. Sit together in a circle and sing and clap along.。
Handbook of Railway Vehicle Dynamics_01 Introduction
1IntroductionSimon IwnickiCONTENTSI.Aims (1)II.Structure of the Handbook (2)I.AIMSThe principal aim of this handbook is to present a detailed introduction to the main issues influencing the dynamic behaviour of railway vehicles and a summary of the history and state of the art of the analytical and computer tools and techniques that are used in thisfield around the world. The level of technical detail is intended to be sufficient to allow analysis of common practical situations but references are made to other published material for those who need more detail in specific areas.The main readership will be engineers working in the railway industry worldwide and researchers working on issues connected with railway vehicle behaviour,but it should also prove useful to those wishing to gain a basic knowledge of topics outside their specialist technical area.Although in the very earliest days of the railways(as described in Chapter2)an individual was responsible for all aspects of the design of a railway,for most of the historical period of railways the vehicles(or rolling stock)have been under the control of mechanical engineers whereas the track has been seen as the domain of civil engineers.The focus of this book being on the vehicles would tend to put itfirmly in the mechanical domain,but in fact,in recent years this rather artificial divide has been lessened as engineers have been forced to consider the railway as a system with the wheel–rail interface at its centre.Increasing use of electrical and electronic components to power, control(or in some cases replace)the basic mechanical components has brought electrical, electronic,mechatronic and control engineers into the teams.The development of equations that represent the complex interactions between a vehicle and the track and of computers able to provide fast solutions to these equations has relied upon the expertise of software engineers and even mathematicians.The topics covered in this handbook are the main areas which impact on the dynamic behaviour of railway vehicles.These include the analysis of the wheel–rail interface,suspension and suspension component design,simulation and testing of electrical and mechanical systems, interaction with the surrounding infrastructure,and noise generation.Some related areas,such as aerodynamics or crashworthiness,are not covered as they tend to use different techniques and tools and have been extensively developed for road or air transport and are reported on elsewhere.The handbook is international in scope and draws examples from around the world,but several chapters have a more specific focus where a particular local limitation or need has led to the development of new techniques or tools.For instance,the chapter on longitudinal dynamics mainly uses Australian examples as the issues related to longitudinal dynamics cause most problems in heavy haul lines such as those in Australia where very long trains are used to transport bulk freight with extremely high axle loads,sometimes on narrow gauge track.Similarly,the issue of structure1gauging largely uses the U.K.as a case study,because here the historic lines through dense population centres have resulted in a very restricted loading gauge.The desire to run high-speed trains in this situation has led to the use of highly developed techniques to permit full advantage of the loading gauge to be taken.The issue of standards has been a tricky one due to the vast number of different organisations who set and control railway standards.It has not been possible to provide comprehensive guidance in this area but typical examples of the application of standards have been brought into the handbook where appropriate.For example,AAR Chapter XI standards for derailment in the U.S.and UIC518for limits on wheel–rail forces in the E.U.are presented.It should be stressed that these are intended only as illustrative examples of how the results of vehicle dynamic analyses can be used,and those with responsibility for safety should check carefully what the relevant current standards are for their work.II.STRUCTURE OF THE HANDBOOKThe history of the field is presented by Alan Wickens in Chapter 2,from the earliest thoughts of George Stephenson about the dynamic behaviour of a wheelset through the development of theoretical principles to the application of modern computing techniques.Professor Wickens was one of the pioneers of these methods and,as director of research at British Rail Research,played a key role in the practical application of vehicle dynamics knowledge to high-speed freight and passenger vehicles.In Chapter 3,Anna Orlova and Yuri Boronenko outline and explain the basic structure of the railway vehicle and the different types of running gear that are commonly used.Each of the relevant components is described and the advantages and disadvantages of the different types explained.The key area of any study of railway vehicle behaviour is the contact between the wheels and the rails.All the forces that support and guide the vehicle pass through this small contact patch,and an understanding of the nature of these forces is vital to any analysis of the general vehicle behaviour.The equations that govern these forces are developed by Hugues Chollet and Jean-Bernard Ayasse in Chapter 4.They include an analysis of the normal contact that governs the size and shape of the contact patch and the stresses in the wheel and rail and also the tangential problem where slippage or creep in the contact patch produces the creep forces which accelerate,brake,and guide the vehicle.The specific area of tribology applied to the wheel–rail contact is explained by Ulf Olofson and Roger Lewis in Chapter 5.The science of tribology is not a new one but has only recently been linked to vehicle dynamics to allow effective prediction of wheel and rail wear,and examples of this from the Stockholm local railway network are presented.Although the main focus of railway vehicle dynamics is traditionally on the vehicle,the track is a key part of the system and in Chapter 6Tore Dahlberg clearly explains the way that track dynamics can be understood.The contribution of each of the main components that make up the track to its overall dynamic behaviour is also presented.Chapter 7covers the unique railway problem of gauging,where the movement of a railway vehicle means that it sweeps through a space that is larger than it would occupy if it moved in a perfectly straight or curved path.Precise knowledge of this space or envelope is essential to avoid vehicles hitting parts of the surrounding infrastructure or each other.David M.Johnson has developed computer techniques that allow the gauging process to be carried out to permit vehicle designers and operators to ensure safety at the same time as maximising vehicle size and speed,and in this chapter he explains these philosophies and techniques.Of fundamental concern to all railway engineers is the avoidance of derailment and its potentially catastrophic consequences.Huimin Wu and Nicholas Wilson start Chapter 8with some statistics from the U.S.that show the main causes of derailment.They go on to summarise the limits Handbook of Railway Vehicle Dynamics 2Introduction3 that have been set by standards to try to prevent these occurrences,and cover the special case of independently rotating wheels and several possible preventative measures that can be taken.Longitudinal train dynamics are covered by Colin Cole in Chapter9.This is an aspect of vehicle dynamics that is sometimes ignored,but it becomes of major importance in heavy haul railways where very long and heavy trains lead to extremely high coupling forces between vehicles. This chapter also covers rolling resistance and braking systems.Chapter10deals with noise and vibration problems,which have become of greater concern in recent years.David Thompson and Chris Jones explain the key issues including rolling noise caused by rail surface roughness,impact noise,and curve squeal.They outline the basic theory required for a study in this area and also show how computer tools can be used to reduce the problem of noise. The effect of vibrations on human comfort is also discussed and the influence of vehicle design considered.In Chapter11,R.M.Goodall and T.X.Mei summarise the possible ways in which active suspensions can allow vehicle designers to provide advantages that are not possible with passive suspensions.The basic concepts from tilting bodies to active secondary and primary suspension components are explained in detail and with examples.Recent tests on a prototype actively controlled bogie are presented and limitations of the current actuators and sensors are explored before conclusions are drawn about the technology that will be seen in future vehicles.Computer tools are now widely used in vehicle dynamics and some specialist software packages allow all aspects of vehicle–track interaction to be simulated.Oldrich Polach,Mats Berg, and Simon Iwnicki have joined forces in Chapter12to explain the historical development and state of the art of the methods that can be used to set up models of railway vehicles and to predict their behaviour as they run on typical track or over specific irregularities or defects.Material in previous chapters is drawn upon to inform the models of suspension elements and wheel–rail contact,and the types of analysis that are typically carried out are described.Typical simulation tasks are presented from the viewpoint of a vehicle designer attempting to optimise suspension performance.Chapter13takes these principles into thefield and describes the main test procedures that can be carried out during the design or modification of a vehicle,or as part of an acceptance process to demonstrate safe operation.Julian Stow and Evert Andersson outline the range of transducers available to the test engineer and the ways that these can be most effectively used to obtain valid and useful data.The necessaryfiltering,corrections,and compensations that are normally made are explained,and data acquisition system requirements are covered.The chapter includes examples of the most commonly carried out laboratory andfield tests.An alternative tofield testing is to use a roller rig,on which,a vehicle can be run in relative safety with conditions being varied in a controlled manner and instrumentation can be easily installed.Weihua Zhang and his colleagues at Southwest Jiaotong University in China operate what is probably the most important roller rig in the world today and they outline the characteristics of this and other roller rigs and the ways in which they are used.Chapter14also reviews the history of roller rigs,giving summaries of the key details of examples of the main types.Chapter15extends the theme to scale testing,which has been used effectively for research into wheel–rail contact.In this chapter P.D.Allen describes the possible scaling philosophies that can be used and how these have been applied to scale roller rigs.In compiling this handbook I have been fortunate in being able to bring together some of the leading experts in each of the areas that make up thefield of railway vehicle dynamics.I and my coauthors hope that this handbook,together with its companion volume,Road and Off-Road Vehicle Dynamics,will be a valuable introduction for newcomers and a useful reference text for those working in thefield.Simon IwnickiManchester。
01_Introduction_no CV
多媒体的定义
狭义多媒体的概念包含几层含义：
媒体的表示形式 处理多种媒体的硬件设备 存储信息的实体
•多种感官作用 •多种仪器设备 •多学科交汇 •多领域应用
•多种信息和码流一体化 •设备控制一体化 •具有实时交互控制环境
多 媒 体
人和客观世界 之间的中介
多媒体技术
利用计算机技术将多种媒体综合一体的技术，使 之建立起逻辑连接，并对它们获取、压缩编码、 编辑、加工处理、存储和展示。 多媒体技术就是把声音、文字、图像、视频等多 种媒体和计算机集成在一起的技术。 学科交叉：数字化信息处理技术、音频处理技术、 图像和视频处理技术、计算机软件和硬件技术、 人工智能和模式识别技术、通信和网络技术等。
课时安排
共48(32+16)学时，其中
授课：30学时（15次） 复习：2学时（1次） 上机实验： 16学时（5次）
考核方式
上机实验
25％
平时成绩(考勤+作业/练习)
5％
期末考试
70％
主要内容
多媒体技术概述 音频处理技术 图像处理技术 视频处理技术 光盘存储系统 基于内容多媒体信息组织与检索 多媒体数据压缩与编码
Audio, Speech & Language Processing @ Northwestern Polytechnical University
多媒体技术导论
Fundamentals of Multimedia Technologies
西北工业大学 计算机学院 陕西省语音图像信息处理重点实验室 音频、语音与语言处理研究组
1.2多媒体技术 的发展与趋势
1.2多媒体技术的发展与趋势
未来的主要发展趋势
分布式、网络化、协同工作的多媒体系统。
Chap.01_Introduction
23
As early as 1816, the vitalistic theory received a heavy blow when Michel Chevreul (米切尔· 欧仁· 谢弗勒) found that soap, prepared by the reaction of alkali with animal fat, could be separated into several pure organic compounds. Without the intervention of an outside vital force.
NH4CN
O NH2 C NH2
By the mid-nineteenth century, the weight of evidence was clearly against the vitalistic theory. H. Kolbe (柯尔柏), 1844，Acetic acid.
M. Berthelort (柏赛罗), 1854, Oil and Fat
Caudate nucleus 尾状核
13
14
Ian Robertson is of Psychology at Trinity College, Dublin “Power and success work through the same circuit as sex and cocaine; it’s a basic, primitive reward system.”
18
History: In Zhou Dynasty, there were some people named “染人”, “醯人” in charge of staining, making wine and making vinegar. But the foundations of organic chemistry date from the mid-eighteenth century, when chemistry was evolving from an alchemist’s art into modern science. At that time, unexplainable differences were noted between substances obtained from living sources and those obtained from minerals.
[耶鲁大学开放课程：聆听音乐].01.Introduction.中英文字幕
![[耶鲁大学开放课程：聆听音乐].01.Introduction.中英文字幕](https://img.taocdn.com/s3/m/340d8fd5b14e852458fb57e4.png)
Its aim is to teach you how to listen to music
有人可能会说 稍等
Wait a minute, you say
这很荒谬
That's preposterous
我天天听音乐的
I listen to music all the time
你这个老家伙
you old goat
你说的没错
And you're right
可能真是这样
You probably do
但是你听的是什么类型的音乐呢
But what kind of music are you listening to
可能是流行音乐 也不错
Well, probably pop music and that's fine
它使我放松
It relaxes me.
好的
Oting.
国家公共广播电台问过
National Public Radio asked
完全相同的问题
exactly this question
在一次一年前的民意调查中
in a survey a year or so ago and
我听了后 接着说 好吧
So I listened to it and I said, "All right
就是这里 你听听这个然后告诉我
Here, you listen to this and tell me
你听到了什么
what you're hearing."
他在录什么
01 Introduction and GA product portfolio positioning
Time
GA
GA VSD, GA+ 现场型和 GA 现已完备 现已完备!
05年12月: 年 月 GA90 06年6月: GA75VSD GA90VSD 年 月 GA55+ GA75+
06年6月: GA30+ GA37+ GA45+ GA55 GA75 年 月 06年10月: GA37VSD GA45VSD GA55VSD 年 月
GAVSD, GA+ WorkPlace and GA
承诺您实现卓越生产力
1
GA 三位一体
从30-90kW,每个功率提供三种GA机型 仅使用了5种不同的结构尺寸，继承了GA质量卓越的传统
超级节能的
经济紧凑的
GA VSD
变频压缩机 性能领先的
GA
压缩机
GA+ 现场型
压缩机
2
GA VSD 优势 – 超级节能
7
利用我们全新、 利用我们全新、多样的产品组合以增加我们的市 场份额
三位一体的GA产品提供了一个可满足多数用户需求的完美组合。 无与伦比的GA品质对所有客户都是物有所值
超级节能的
GA VSD
经济紧凑的
GA
变频压缩机
压缩机
性能领先的 GA+ 现场型 压缩机
8
承诺您实现卓越生产力 …
超级节能的
GA VSD
经济紧凑的
GA
变频压缩机
压缩机
性能领先的 GA+ 现场型 压缩机
9
通过互动与创新， 通过互动与创新， 我们承诺您实现卓越生产力！ 我们承诺您实现卓越生产力！
10
07年1月: 年 月 GA15 GA18 GA22 GA11 GA15 GA18 GA22 GA30 ELII 和 ELI 计划在2008年推出新款设计 计划在 年推出新款设计 07年1月: 年 月 GA30+ GA37 GA45
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
Design and Analysis of Algorithms1. IntroductionMingyu XIAOSchool of Computer Science and Engineering University of Electronic Science and Technology of ChinaWelcome!Are you thinking about these questions? Why do we need to study this course? What should we learn in the course? How about the instructor? Is it hard to pass the exams? What is different from the undergraduate course?NO PROBLEM1.1 Course InformationCourse InformationLecture time and venue: Time: Tuesday(5-6), Friday(3-4). The first ten weeks Venue: B409, the second teaching building (Qingshuihe campus) Language: Chinese + English Instructor: Dr. XIAO Mingyu (肖鸣宇) Email: myxiao@ Tel: 153-97626165 Course page: Announcements and lectures are released in: algorithm_uestc@ (passwords: algorithm)2008@Hong Kong4Course InformationSyllabus: Introduction (2 hours) Basics of algorithm design & analysis (8 hours) Flows (4 hours) NP-Completeness and Appro. alg. (10 hours) Advance topics (12 hours) Practices (4 hours) Textbook:J. Kleinberg， E. Tardos, Algorithm design，Addison Wesley， 2005算法设计与分析基础 网络流 NP完备性和近似算法 算法高级讲座 课程设计Reference:Cormen，Leiserson，Rivest，Stein，算法导论（影印版），高等教育出版社，2007Grading Scheme:Final exam 70% Practices and others 30%5Course InformationData from 2014: Attended final exam: 164 (Registration: 175) 考试 137 考查 27考试137 人 3 40 65 20 9 90分 80分 70分 60分 不及格 考查 27人 18人通过Data from 2013 : Attended final exam: 144 (Registration: 163) 考试 100 考查 44考试100 人 2 20 57 17 4 90分 80分 70分 60分 不及格 考查 44人 41人通过6Course InformationData from year 2012 : Attended final exam: 151 (Registration: 163) 考试 106 考查 45考试106 人 6 35 33 14 8 90分 80分 70分 60分 不及格 考查 45人 35人通过7Course Information2014年冠军榜(卷面分数) 第一名：93分，王治， 计算机系统结构 陈均滔，计算机系统结构 第三名：88分，张玖林，通信与信息系统 周令辉，通信与信息系统 第五名：87分，胡海啸，计算机软件与理论 王飞， 计算机技术 2013年冠军榜 第一名：90分，周志惠， 计算机软件与理论 周佼， 计算机应用技术 第三名：87分，姜晓， 计算机应用技术 第四名：86分，甘茂然， 计算机系统结构 王浩， 信息与通信工程（考查）8Course InformationAdvices to who wants to register this course: 1. This course is worthy of your time. You will be proud of yourself when you fall in this course. 2. This course may be a heavy load for you, if you donot want to spend time on it. So DON’T select this course if you just want to get the credit. 3. Read the lecture notes carefully, which will be more helpful for you than the text books. 4. Make sure that you can solve the problems that I put highlines in the course. 5. In some interviews of job hunting, you may find the techniques in the course useful.91.2 IntroductionComputers v.s. TractorsWhat is the difference between the two machines?v.s.Computers are more powerful?11Computer ProblemsProblem：A task to be performed by computers• Problems ⇔ Mathematical function from inputs tomatching outputs.• A particular input must always result in the sameoutput every time the function is computed• Problem definition should include constraints on theresources that may be consumed by any acceptable solution12Three Kinds of ProblemsDecision Problem (with yes-no answers) e.g. Is there a solution better than some given bound? Optimal Value/Optimal Solution e.g. What is the value of a best possible solution? e.g. Find a solution that achieves the optimal value Numerical Calculation e.g. Solving an equation group13AlgorithmsWhat is an algorithm?1. a method or a process followed to solve a problem using a computer 2. takes the input of a problem and transforms it to the output 3. A problem can have many algorithmsProblem Algorithm ProgramInputsComputerOutputs14Programs and algorithms• A computer program is an instance, or concreterepresentation, for an algorithm in some programming language.• A program is to be read by computer • An algorithm is to be read by human being • Algorithms can be expressed by pseduocodes or justsome short steps that are easy to read and understand15Goals of Algorithm Design• We want to use computes to solve problems--To solve problems under the recourse constrainsTwo ‘conflicting’ goals : To design an algorithm that is easy to understand, code and debug. To design an algorithm that makes efficient use of the computer’s resources.16Good Algorithms Always Exist?• Some problems have good algorithms and can besolved quickly. Some may not have (we have not found good algorithms yet).• What should we do for hard problems?-believing that there are some good algorithms for them? -believing that these problems are fundamentally different from easy problems?17Different Classes of Problems• 人类认识世界的一个共同规则：物以类聚 • Computational complexity.Classify the problems into different classes by measuring the minimum resource (running time, space, or others) required to solve the problem.• Some important classes:P, NP, NPC, PTAS,…18Different Classes of Problems• P: a solution can be solved in polynomial time. • NP: a solution can be checked in polynomial time. • NPC: problems that may not have polynomial-timealgorithms.NPCPNPP = NP? 植物是否等同动物？• Many important problems in practice are NPC.19NPC Problems• Many methods to deal with NPC problems: • Heuristic algorithms: solving the problems by yourfeeling. Donot know if it is right or not, but the algorithm runs fast.• Approximation algorithms: the algorithm finds asolution not far away from the optimal solution and runs in polynomial time.• Fast exact algorithms: effective exponential-timealgorithms (must faster than simple search algorithms). when the parameter is small.• Parameterized algorithms: the algorithm is effective20。