U5-Figure Interepreting-1

新编英语教程5课文翻译(unit1-15) Unit 1 恰到好处你见过一个笨手笨脚的男人往箱子上钉钉子吗？只见他左敲敲，右敲敲，说不准还会将整个钉子锤翻，结果敲来敲去到头来只敲进了半截。

而娴熟的木匠就不这么干。

他每敲一下都会坚实巧妙地正对着钉头落下去，一钉到底。

语言也是如此。

一位优秀的艺术家谴词造句上力求准确而有力地表达自己的观点。

差不多的词，不准确的短语，摸棱两可的表达，含糊不清的修饰，都无法使一位追求纯真英语的作家满意。

他会一直思考，直至找到那个能准确表达他的意思的词。

The French have an apt（贴切的） phrase for this. They speak of “le mot juste,”法国人有一个很贴切的短语来表达这样一个意思，即“le mot juste”, 恰到好处的词。

有很多关于精益求精的作家的名人轶事，比如福楼拜常花几天的时间力求使一两个句子在表达上准确无误。

在浩瀚的词海中，词与词之间有着微妙的区别，要找到能恰如其分表达我们意思的词绝非易事。

这不仅仅是扎实的语言功底和相当大的词汇量的问题，还需要人们绞尽脑汁，要观察敏锐。

选词是认识过程的一个步骤，也是详细描述我们的思想感情并表达出来使自己以及听众和读者深刻理解的一个环节。

有人说：“在我思想未成文之前，我怎么知道自己的想法？”这听起来似乎很离谱，但它确实很有道理。

It is hard work choosing the right words, but we shall be rewarded by thesatisfaction that finding them brings. The e某act use of language gives us mastery（掌握） over the material we aredealing with. Perhaps you have been asked “What sort of a manis so-and-so（等）?” You begin: “Oh, I think he’s quite anice chap （家伙）but he’s rather…” and then you hesitate trying to find a word or phrase to e某press what it is abouthim that you do n’t like, that constitutes（构成） hislimitation. When you find the right phrase you feel that your conception of the man is clearer and sharper.寻找恰如其分的词的确是件不容易的事。

REV. DE CIÊNCIA & TECNOLOGIA, Piracicaba, v. 11, n. 21, p. 1-73, jan./jun. 2003.R EVISTA DE C IÊNCIA& T ECNOLOGIA • 211COMISSÃO EDITORIALN IVALDO L EMOS C OPPINI – presidente (Engenharia de Produção) K LAUS S CHÜTZER (Engenharia Mecânica)N ELSON C ARVALHO M AESTRELLI (Gestão da Produção)N IVALDI C ALONEGO JÚNIOR (Ciência da Computação)SÔNIA M ARIA M ALMONGE (Engenharia Química)COMITÊ CIENTÍFICOB ERT L AUWERS (Katholieke Universiteit Leuven –Bélgica)C ARLOS A LBERTO G ASPARETTO (Facens/Unicamp –ESTEVAL project partners.– Feature Based Integrated Design Environment.Identification of interdependencies between manufacturing features.Unsuitable finishing quality (Schützer et al., 1999).After considering several possibilities, which could result in this poor surface quality cutting tool geometry , clamping and balancing of the tool system, technological parameters and machining set-ups, it was realized, that the problem came from the CNC of the machine tool, which was incapable of processing the NC program as fast as the feed rate defined in the NC program. So the machine reaches the point refereed in one line of the program and the information to move the tool to the next point was not processed yet, then the machine had to wait a couple of milliseconds to start moving again.This incompatibility between the feed rate defined in the NC program and the processing time of the CNC results in two different situations according to the CNC used:poor surface quality – the CNC tries to move the machine at the programmed feed rate, but it can-Improper surface finishingThe workpiece used and the finishing tool path.The roughing and semi-finishing operations were accomplished using exactly the same technological parameters and cutting strategies for all workpieces.The comparison analysis was done only during the finishing operation and the same technological para-meters, cutting strategies and tools were used in both cases. The finishing operation was distinguished by the methodology of interpolation. The trajectory of the finishing tool path is shown in figure 3. For this operation it was used a 10 mm ball end mill tool at 10000 rpm and the programmed feed rate was 2000 mm/min.YSISThe results of the machining experiments considering the NC program size, the time required to exe-cute the program and the surface quality in terms of roughness and superficial texture were compared and the conclusions are presented below.NC Program SizesThe table 2 presents the finishing programs sizes calculated for both methods. It proves that less infor-mation are required to describe tool paths by the circular/linear method, thus reducing the program size byMETHOD P ROGRAM SIZE N UMBER586 kbCircular/linear83 kb• V. 11, Nº 21 – pp. 29-36Regions where the feed rate as reduced.2000 mm/min660 mm/min 1500 mm/min700 mm/min2000 mm/minRoughness AnalysisIt was used a digital Surftest Equipment to obtain the Ra and Rz parameters. It was analyzed the same areas for all workpieces. Practically, there are not differences between the roughness parameters for both interpolation methods.Surface T exture AnalysisIt was possible to visually verify the differences between the surfaces of both methods. The circular/ linear workpieces are smoother than the linear ones. The figure 5 shows this texture.Irregular surface texture Regular surface textureBesides those transversal marks at the workpiece machined by the linear interpolation, this method also gives a deficient quality in the longitudinal direction, as it is seen in the next photos taken by a CCD camera connected in an microscopy.Figure 6 was taken using a microscopy with magnification 10x of the linear part. The vertical marks are the cusp heights left by the ball end mill tool. The steps-over of the tool path is on the horizontal direc-Fig. 6. Uneven cusps from a linear workpiece.Fig. 7. Even cusps from a circular/linear workpieceIn linear interpolation method is possible to see uneven cusp heights, what can difficult drastically the hand finishing afterwards. This problem is not seen at the workpieces milled by the circular/linear method, as shown in figure 7. It happens due to the more constant cutting movements.In this method, the cusps height are much more uniform, what can help the manual finishing afterwards, by decreasing this process time, and improving the accuracyCONCLUSIONThe High Speed Cutting T echnology can be attractively applied in die and mould manufacturing, among others applications. However, there are several other technologies in the process chain that must be considered to support an efficient HSC process.R EVISTA DE C IÊNCIA & T ECNOLOGIA • V. 11, Nº 21 – pp. 29-36。

1.1 A Closer Look at the Processor and PrimaryStorage仔细看看处理器和主存储器We have learned that all computers have similar capabilities and perform essentially the same functions, although some might be faster than others. We have also learned that a computer system has input, output, storage, and processing components; that the processor is the “intelligence” of a computer system; and that a single computer system may have several processors. We have discussed how data are represented inside a computer system in electronic states called bits. We are now ready to expose the inner workings of the nucleus of the computer system — the processor.我们已经知道，所有的计算机都具有相似的能力，并且在本质上执行相同的功能，尽管一些可能会比另一些快一点。

我们也知道，一个计算机系统具有输入，输出，存储和处理部件；处理器是一个计算机系统智能核心，并且一个计算机系统可以有许多个处理器。

我们已经讨论过如何在计算机系统内部，用被称作“位”的电子状态来表现数据，现在我们要弄明白计算机系统的核心，即处理器，的内在的工作方式。

Unit 5Data ProcessingChapter Two&Part4 Extensive Reading @Part 1 Notes to Text@Part5Notes to Passage & Part 2 Word Study@Part3 Practice on Text @Part6 Practice on Passage@Part 1 Notes to TextData Processing1)data processing: 遥感数据处理是指通过各种技术手段对遥感探测所获得数据进行的各种处理。

2) While the object or phenomenon of interest may not bedirectly measured, there exists some other variable that can be detected and measured by the observation, which may berelated to the object of interest through the use of a data-derived computer model.虽然就凭观察难以直接测量和判断人们所感兴趣的物体或现象，但是却能测出和判断出其中的某种变化。

通过计算机数据源模型可以使这种变化与令人感兴趣的物体关联起来。

注释：连接词while引导让步状语从句，意为“虽然、尽管”；引导词there放在句首，引起主、谓语倒装；which引导非限制性定语从句，指代的是some other variable。

3) Spatial resolution refers to the size of a pixel that is recorded in a raster image –typically pixels may correspond to square areas ranging in side length from 1 to 1000 metres. 空间分辩率是指摄录在栅格图像中像素的大小—典型的像素相当于边长为一至一千米的任一正方形面积。

1. Properly used, intelligence tests can provide valuable diagnostic information and insights about intellectual ability that might otherwise be overlooked. ignored2. In the last months of World War II(1939-1945), Allied forces urged Japan to surrender unconditionally or face “prompt and complete destruction”. utter3. Wetlands play a crucial role in the environment cycle. They provide important wildlife habitat, can prevent flooding, and help clean polluted water through natural filtering processes. contaminated4. Thanks to a very effective and powerful combination of advancing technology and government incentives, renewable energy may finally be coming of age. potent5. Experiments confirm an observation experienced by most people: One can forget some information at one point in time and yet be able to get it back perfectly well at a later point. retrieve6. Jimmy Carter asked large businesses to hold down prices and labor unions to avoid new wage demands. Unluckily, his words had little effect. Unfortunately7. The captain was the last crew member to be lifted to safety be the helicopter. hoisted8. The term “learning” they are speaking about is the process involved in the initial acquisition or encoding ofinformation, whereas the term “memory”more often refers to later storage and retrieval of information.referring to9. Eventually Mrs. Jones reluctantly accepted the demand that she resign at once. bowed to10. After the 1991 Persian Gulf War, the IAEA(International Atomic Energy Agency) inspectors discovered anddismantled(废除) Iraq’s secret nuclear weapons program. uncover11. It took them a very long time to get over the shock of the terrorist attack on the World Trade Center.12. I got to thinking about his childhood and how different it must have been to mine.13. There was an abrupt drop in the temperature. We found it hard to get through the remaining days in theout-of-the-way village.14. They had to get over one or two technical problems before filming could start.15. We can get by on our income at the moment, but we’ll need more money when the baby arrives.16. Mason always felt horribly embarrassed when people started to cry, and tried to think excuse to get away.17. We would have come straight here, except our flight got in too late.18. We have really got to get this book out by the end of the year.19. My brother and I used to argue a lot but we get along fine now that we have got married and have our ownchildren.20. Yesterday I managed to get away with parking in a “no parking” zone.Unit 31.Mary invited us to her birthday party last week, and we received the written request to particular yesterday.invitation2.It is known to all that facts are powerfully persuasive and convincing, speaking louder than words. eloquent3.My father taught me how to keep two or more objects in the air at one time by alternately tossing andcatching them when I was a child. It took me weeks of practice before could do it with three balls. juggle 4.It is often vital for a leader to listen to different views on an issue, even if these views are conflicting.contradictory5.In traditional societies, parents transmitted their own values to their children in the warmth and closeness offamily relations. intimacy6.Histories differ in their opinions about the lessons of history, and so there are many different interpretations ofthe past. disagree7.It is difficult to draw a general conclusion about student who are gifted because their characteristics and needsare so personal and unique. generalize8.Miya blushed with a feeling of shame when she realized how foolish she was being. embarrassment9.My brother said that John looked like a bear, so that’s what I’m calling him at present. for now10.Speaking at an international conference, Dr.Young pointed out that police officers should use force only if allother ways fail and that the amount of force must be in proportion to the threat they encounter. as a last resort11.In some remote and underdeveloped areas of the country, children have to attend a school where there are notextbooks, or too few to go around/round.12.The future is promised to no one. Go for it now.13.The little girl was scared when all the lights suddenly went off and the house was plunged into darkness.14.A does of poison can do its work but once. A bad book can go on poisoning minds for generations.15.She is always on the go, and how she finds time to write and keep us informed of what is going on is beyondme.16.Setting a goal is not the main thing. It is deciding how you will go about achieving it and staying with thatplan.17.He knows she is not yet convinced, but is telling her to trust him and go along with what he says.18.Some people go through life trying to find out what the world holds for them, but very often they only findout too late that it’s what they bring to the world that really what he says.19.I like to sit on the bank watching the river go by.20.Once your data are collected, you will need to go over the statistics and make sure you are doing the analysiscorrectly.Unit 41.When the performance was over, the audience were asked to leave in an organized fashion. orderly2.Both home-made and important high-resolution TV sets are available, but the imported high-resolution TV setis more expensive. latter3.Sheila should not get lost because I gave her very clearly stated directions how to get here. explicit4.The chief executive praised Mr. Smith for coming up with new ideas for raising productivity. commended5.The task of organizing the spring trade fair has been assigned to two senior officials. entrusted6.Jenny was a student of medicine before she started writing as a career. turned to7.Not happy about having upset my parent with his rudeness, he then went and insulted my sister! Notcontent with8.I don’t know how you can boldly face your friend after the damage you have done to his business. lookyour friend in the face9.Both man and animal need a sense of security to survive and thrive. beast10.As soon as Lucy saw him, a curious look creased her face, a look of puzzlement, as if she was trying to placehim. perplexity11.She turned to drugs after the breakup of her fifteen-year marriage.12.Many boys proposed to Lynn, but she turned them all down.13.A man without training works at whatever jobs turn up.14.It turned out that Phil’s forecast was entirely wrong: The stock market was going bullish rather than bearish.15.Mrs. Jackson took her son Tommy to the school and turned him over to the headmaster.16.As soon as she got home Ann entered the living room and turned on the TV.17.The camp was already full and many of the refugees had been turned away.18.Martin turns out a poem each weak for the school paper.19.When the football season was over, we turned in our uniforms to the club.20.Stan kept working until well beyond midnight, as he wanted to finish the second draft before turning in.Unit 61.She did noting in the office but read newspapers, digesting every piece of news. fragment2.It seems to me it is not worth it to argue about such a small sum of money. an insignificant3.Betty was small and fragile and looked rather strange in army uniform. incongruouste that night, the local residents heard the sound of big guns roaring in the distance. thundering5.She picked a lemon from the tree in the garden, sliced it and squeezed some juice over the dish. plucked6.The Advancement Office has done a huge amount of fund raising in the past year. terrific7.Five big trucks stopped in front of the supermarket and began to unload their cargo. pulled up8.Two names have been struck out from the list and it is vital to find out who they are. scratched out9.In the midst of loud applause, the candidate walked quickly with big steps to the platform and began todeliver his well-rehearsed speech. strode10.Even though war seemed inevitable, their efforts to prevent in never stopped. ceased11.If you are doing office work, you’d better take up some outdoor sports as a relaxation.12.As Robert had reached the age of 45 without getting married, it was obvious that he was not the sort of manwho takes to matrimony（婚姻）like a duck to water.13.The airplane pilot suddenly fainted and his copilot had to take over.14.I can’t take on exact work. I’ve had my hands full recently.15.Owing to the unexpected thunderstorm our plane took off two hours late.16.At the press conference held by the Pentagon yesterday reporters were seen taking down every word of whatthe spokeswoman said.17.I took back my offer to buy the house as its surroundings were not so good as the real estate agent claimed.18.About two weeks after the interview Linda was taken on as a tax analyst and went to work in the taxdepartment of the company.19.“You’re not fond of work, are you?” said the father, --“No. I take after you,” replied the smart yet lazy boy.20.She took all the children in with her monster story.Unit 71.Familiar things happen, and mankind does not bother about them. It requires a very unusual mind toundertake the investigation or study of the obvious. analysis2.Each one of the most simple parts of all matter is a microcosm（微观世界）, and faithfully renders the likenessof the world. particle3.Nothing is certain in life, but generally the chances of happiness are greater if one has many areas of interestand involvement. multiple4.Curiously, in our world of big names, our true heroes tend to be unknown. anonymous5.Journalism is the art of collecting varying kinds of information that a few people possess and of passing italong to a much larger number of people who are supposed to desire to share it. transmitting6.North Shore Magazine is a magazine published once a month that offers stories on significant issues andpeople who live in the northern suburbs and on the north side of Chicago. monthly7.It will be agreed that the essential difference between humour and wit is that, where as wit is alwaysinternational, humour is never something conceived with a purpose. unintentional8.I was stuck in the elevator last Friday. On top of that, I forgot to take my cell phone. To make matters worse9.To make sure that our customers receive our message in time, if a recipient’s phone is turned off or out ofcoverage, the message will be sent again, for up to 7 days, until it is received by the phone. resent10.The purpose of the festival is also to emphasize the importance of education and life long learning in thecontext of globalization. highlight11.On the evening before my trip to the small island off the coast of Australia, I carefully laid out everything I’dneed for the three months of my stay there.12.In some industries, production or spending cuts and various other circumstances can cause employers to layoff workers.st Friday our class laid on a special tea and entertainment for the workmen who had remodeled ourclassroom.14.Now that the new rules have been lain down, we must adhere to them faithfully.15.Sullivan has been laid up since Monday with a sore throat and fever.16.Everyone asked where I was during lunchtime. Since I didn’t want to tell them, I made up some excuse aboutseeing the dentist.17.Ruth’s writing is very small. I almost need a magnifying glass to make it out.18.Everyone is trying to accomplish something big, not realizing that life is made up of little things.19.John rose from the chair and made for the balcony.20.The couple next-door had a fight last night, but they soon made up and looked as if nothing had happened.。

Attentionisallyourneed（原⽂翻译）注意⼒是你所需要的摘要：占优势的序列转换模型基于复杂的循环或卷积神经⽹络，其中包括⼀个编码器和⼀个解码器。

表现最好的模型还通过注意⼒机制连接编码器和解码器。

我们提出了⼀种新的简单的⽹络架构，即Transformer，它完全基于注意⼒机制，完全摒弃了递归和卷积。

在两个机器翻译任务上的实验表明，这些模型在质量上更优越，同时具有更强的并⾏性，需要的训练时间明显更少。

我们的模型在WMT 2014英语-德语翻译任务上实现了28.4个BLEU，⽐现有的最佳结果(包括集成)提⾼了超过2个BLEU。

在WMT 2014英法翻译任务中，我们的模型在8个GPU上进⾏了3.5天训练后，建⽴了⼀个新的单模型最先进的BLEU分数为41.8，这是⽂献中最好模型的训练成本的⼀⼩部分。

通过成功地将Transformer应⽤于⼤量和有限的训练数据的英语选区解析，我们证明了它可以很好地推⼴到其他任务。

1、引⾔循环神经⽹络，特别是长短期记忆[13]和门控循环[7]神经⽹络，已经被确定为序列建模的最先进的⽅法语⾔建模和机器翻译等转导问题[35,2,5]。

从那以后，⼤量的努⼒继续推动循环语⾔模型和编码器-解码器架构的边界[38,24,15]。

循环模型通常沿着输⼊和输出序列的符号位置进⾏计算。

在计算时间中，将位置与步长对齐，它们⽣成⼀个隐藏状态序列，作为前⼀个隐藏状态和位置t输⼊的函数。

这种固有的序列性质妨碍了训练⽰例中的并⾏化，这在序列长度较长的情况下变得⾄关重要。

由于内存约束限制了跨⽰例的批处理。

通过因式分解技巧[21]和条件计算[32]，最近的⼯作在计算效率⽅⾯取得了显著的改进，同时也改善了后者的模型性能。

然⽽，顺序计算的基本约束仍然存在。

注意机制已经成为各种任务中引⼈注⽬的序列建模和转换模型的组成部分，允许建模依赖关系，⽽不考虑它们在输⼊或输出序列中的距离[2,19]。

然⽽，在所有[27]案例中，这种注意机制与循环⽹络⼀起使⽤。

u校园新探索研究生英语unite5 -回复the following questions:1. What are the benefits and challenges of studying abroad?2. How can studying abroad help improve language proficiency?3. What cultural experiences can be gained through studying abroad?4. What are some tips for adjusting to a new academic environment while studying abroad?5. How can studying abroad contribute to personal and professional growth?Studying abroad has become increasingly popular among graduate students as it offers a range of benefits as well as some challenges. In this article, we will explore the advantages and disadvantages of studying abroad, focusing on language proficiency improvement, cultural experiences, academic adjustment, and personal and professional growth.One of the main benefits of studying abroad is the opportunity to immerse oneself in a foreign language environment. By living and studying in a foreign country, graduate students are constantlyexposed to the target language, which enhances their language skills significantly. Daily interactions with local residents, attending classes conducted in the target language, and learning from native speakers are all effective ways to improve language proficiency. Moreover, studying abroad provides the chance to acquire specialized vocabulary and language skills related to the graduate program, which is often not available in one's home country.Cultural experiences are another important aspect of studying abroad. Living in a different culture allows graduate students to broaden their horizons, develop intercultural communication skills, and gain a deeper understanding and appreciation for different customs and traditions. Exploring local landmarks, participating in cultural events, and building relationships with local residents are all valuable experiences that contribute to personal growth and global perspectives.However, studying abroad also comes with its challenges. Adjusting to a new academic environment can be daunting as educational systems, teaching methods, and assessment criteria may differ from one's home country. It may take time to adapt to new learning styles, expectations, and academic demands.Graduate students studying abroad may also face the challenge of language barriers, which can hinder effective communication and academic performance. Additionally, being away from familiar support networks and facing homesickness can be emotionally challenging.To overcome these challenges, it is important to be proactive in adjusting to a new academic environment. This includes attending orientation programs and workshops, seeking guidance from academic advisors, and building relationships with fellow students. Taking advantage of support services offered by the host institution, such as language courses and tutoring programs, can also aid in overcoming language barriers. Developing effective time management skills and seeking a balance between academic and personal life is crucial to maintaining overall well-being.Studying abroad offers immense personal and professional growth opportunities. It allows graduate students to develop independence, adaptability, and resilience in a new environment. Cultural immersion and intercultural experiences enhance communication skills, cultural sensitivity, and global awareness, which are highly valued in today's interconnected world. Theexperience of studying abroad also demonstrates an individual's ability to step out of their comfort zone and embrace new challenges, which is highly regarded by employers and graduate programs.In conclusion, studying abroad provides numerous benefits and challenges for graduate students. While it can improve language proficiency, offer cultural experiences, and contribute to personal and professional growth, it also requires adjustments to a new academic environment. By being proactive, seeking support, and maintaining a positive mindset, graduate students can make the most of their study abroad experience and achieve their academic and personal goals.。

ComprehensionI. Judge which of the following best summarizes the main idea of the article.A. To be able to use the right word is an important component of one’s mastery of the English language.B. To facilitate one’s own process of cognition and one’s communication with others, one must be able to choose the right word from the extensive vocabulary of the English language.C. It is more important to know exactly the meaning and use of a relatively small number of words than to know vaguely a larger number.II. Determine which is the best choice for each of the following questions.1. “Clean English” in the first paragraph means .A. English of a dignified styleB. English free from swear wordsC. English which is precise and clear2.The word “realization” in the sentence “Choosing words is part of the process of realization…” means .A. articulating soundsB. fulfilling one’s goalsC. becoming aware of what one thinks and feels3. The example given in para. 3 of a man searching for the right word for his feelings about his friend illustrates the function words perform in .A. defining out thoughts and feelings for ourselvesB. defining our thoughts and feelings for those who hear usC. both A and B4. The word “cleanly” in the last sentence means .A. squarelyB. clearlyC. neatly5.The examples of the untranslatability of some words given in para. 11 best illustrate which sentence of the paragraph?A. The first sentence.B. The second sentence.C. The third sentence.III. Answer the following questions.1. Which sentence in the first paragraph establishes the link between the driving of a nail and the choice of a word?2. What does the word “this” in sent ence 1, para. 2, refer to?3. Do you agree with the author that there is a great deal of truth in the seemingly stupid question “How can I know what I think till I see what I say”?Why or why not?4. Explain why the word “imprison” in the example given in para. 9, though not a malapropism, is still not the right word for the writer’s purpose.5. What is the difference between “human” and “humane”? And the difference between “human action” and “humane action”, and also that between “human killer” and “humane killer”?6. What does the word “alive” in the sentence “a student needs to be alive to these differences” (para. 9) mean?7. Why is it difficult and sometimes even impossible to translate a word from one language into another as illustrated in para. 11? Supply some such examples with English and Chinese.8. The writer begins his article with an analogy between the unskilled use of the hammer and the improper choice of words. Identify the places where the analogy is referred to in the rest of the article.Language WorkI. Read the following list of words and consider carefully the meaning of each word. Then complete each of the sentences below using the correct form of an appropriate word from the list.Creep Loiter March Meander Pace Patrol Plod Prowl Ramble Roam SaunterShuffle Stagger Stalk Step Stride Strut Stroll Toddle Tramp Tread Trudge Walk1. After the maths examination Fred, feeling exhausted, across the campus.2. The soldiers reached their camp after 15 miles through the deep snow.3. It is pleasant to in the park in the evening.4. After the cross-country race Jack to the changing room.5. Last night when he sleepily to the ringing telephone, he accidentally bumped into the wardrobe.6. We saw him towards the station a few minutes before the train’s departure.7. The old couple through the park, looking for a secluded bench to sit on and rest.8. The newly-appointed general about the room like a latter-day Napoleon.9. Peter whistled happily as he along the beach.10. These old people liked to about the antique ruins in search of a shady picnic spot.11. Many tourists about the mall, windowshopping.12. We were fascinated by the view outside the room----a beautiful verdant meadow and brooks through it.13. Mary used to about the hills and pick wild flowers for her mother.14. Eager to see the pony in the stable, the children down the staircase, their hearts pounding violently.15. The lion had the jungle for a long time before it caught sight of a hare.16. My brother began to when he was ten months old.17. The farmers often let their horses freely in the meadow so that they could eat their fill of grass.18. The patrols were along through the undergrowth when the bomb exploded.19. The thugs were reported to be the streets for women workers who were on their way home after the afternoon shift.20. The first-year students not only learned how to , they were also taught how to take aim and shoot when they had military training.21. Sometimes Tom, our reporter, would up and down the study, deep in thought.22. When he was Third Street, Fred found the little match girl lying dead at the street corner.23. Secretaries hated seeing their new manager in and out of theoffice without even casting a glance at them.24. Mother asked us to lightly so as not to wake Granny.25. The refugees for miles and miles all day hunting for a place to work.26. When the pop singer out of the car, his fans ran to him, eager to get his autograph.27. The laborers on their way home after working in the plantation the whole day.28.The lion was feeling pretty good as he (A) through the jungle. Seeing a tiger, the lion stopped it.“Who is the King of the jungle?” the lion demanded.“You, O lion, are the King of the jungle,” replied the tiger.Satisfied, the lion (B) on, until he came across a large, ferocious-looking leopard.“Who is the King of the jungle?” asked the lion, and the leopard bowed in awe. “You, mighty lion, you are the King of the jungle,” it said humbly and (C) off.Feeling on top of the world, the lion proudly (D) up to a huge elephant an d asked the same question. “Who is the King of the jungle?”Without answering, the elephant picked up the lion, swirled him round in the air, smashed him to the ground and jumped on him.“Look,” said the lion, “there’s no need to get mad just because you didn’t know the answer.”II. Make a list of more specific words for each of the following general terms. For example, for WALK, you could list stride, stroll, saunter, plod, toddle and so on. Give sentences to illustrate how the words may be used.1. SAY2. SEE3. BEVERAGE4. EXCITEMENT5. DELIGHT6. SKILFULIII. In the following sentences three alternatives are given in parentheses for the italicized words. Select the one which you think is most suitable in the context.1. A clumsy (heavy, stupid, unskillful) workman is likely to find fault with his tools.2. As John was a deft (skillful, clever, ready) mechanic, he was hired by the joint-venture in no time.3. The writer made a point of avoiding using loose(vague, unbound, disengaged) terminology in his science fiction.4. We didn’t appreciate his subtle(delicate, tricky, profound) scheme to make money at the expense of the customers.5. Annie Oakley became famous as one of the world’s most precise (accurate, scrupulous, rigid) sharpshooters.6. The government in that newly-independent country has decided to make ashift (alteration, turn, transference) in its foreign policies.7. Misunderstanding arose on account of the vague(undetermined, confused, ambiguous) instructions on the part of the manager.8. If soldiers do not pay scrupulous (exact, vigilant, conscientious) attention to orders they will not defeat the enemy.9. In some areas, the virgin forest has been cut through ignorance (blindness, want of knowledge, darkness) of the value of trees.10. Since many pure metals have such disadvantages (harm, unfavourableness, drawbacks) as being too soft and being liable to rust too easily, they have little use.11. My colleague, Mr. Hill, has a small but well-chosen library, where it is said he spends most of his spare time cultivating(nourishing, tilling, developing) his mind.12. If you think photography is my hobby, your belief is quite mistaken (fraudulent, erroneous, deceitful).13. What appears to the laymen as unimportant (minute, trivial, diminutive) and unrelated facts is often precious to the archaeologist.14. The lounge has a seating capacity of 30 people but it is too dark (dim, dingy, gloomy) to read there.15. These career-oriented women are used to flexible (adaptable, willowy, docile) working hours in the office.16. Only experts with a professional eye can tell the fine(fair, pleasant,subtle) distinction between the two gems.17. The goose quill pen has a great sentimental (tender, emotional, soft) appeal to Emily as it was a gift from her best friend.18. Being thoughtful of and enthusiastic towards others is the essence (gist, kernel, quintessence) of politeness.19. When Iraq destroyed some of its nuclear and chemical weapons, it acted under coercion (repression, concession, compulsion).20. My uncle’s oft-repeated anecdotes of his adventures in Africa were fascinating (catching, pleasing, absorbing ) to listen to.IV. Give one generic term that covers each of the following groups of words.1. artificer, turner, joiner, carpenter, weaver, binder, potter, paper-cutter2. volume, brochure, pamphlet, treatise, handbook, manual, textbook, booklet3. painter, sculptor, carver, poet, novelist, musician, sketcher4. grin, smirk, beam, simper5. donation, subscription, alms, grant, endowment6. bandit, poacher, swindler, fraud, embezzler, imposter, smuggler7. nibble, munch, devour, gulp8. drowse, doze, slumber, hibernate, coma, rest, nap9. manufacture, construct, weave, compose, compile10. ancient, antique, old-fashioned, obsolete, archaic11. slap, tap, pat, thump, whack12. alight, descend, dismount, disembarkV. Fill in each blank with an appropriate word.In discussing the relative difficulties of analysis which the exact and inexact sciences face, let me begin with an analogy. Would you agree that swimmers are (1) skilful athletes than runners (2) swimmers do not move as fast as runners? You probably would (3) . You would quickly point out (4) water offers greater (5) to swimmers than the air and ground do to (6) Agreed, that is just the point. In seeking to (7) their problems, the social scientists encounter (8) resistance than the physical scientists. By (9) I do not mean to belittle the great accomplishments of physical scientists who have been able, for example, to determine the structure of the atom (10) seeing it. That is a tremendous (11) yet (12) many ways it is not so difficult as what the social scientists are expected to (13) . The conditions under which the social scientists must work would drive a (14) scientist frantic. Here are five of (15) conditions. He can perform (16) experiments; he cannot measure the results accurately; he (17) control the conditions surrounding (18) experiments; he is of the expected to get quick results(19) slow-acting economic forces; and he must work with people,(20) with inanimate objects…VI. Following Warner’s model of establishing an analogy between two dissimilar things, write a passage, discussing the learning of a foreign language. You are supposed to use an analogy to help you explain. For instance, you may compare the learning of a foreign language to that of swimming, bike-riding, etc.UNIT 1 TEXT 1Exercises KeysComprehension:I. B ;II. 1.C 2.C 3.C 4.A 5.C ;III. 1. “So with language; …firmly and exactly.”2. Getting the word that is completely right for the writer’s purpose.3. Yes, I do. It sounds irrational that a person does not know what he himself thinks before he sees what he says. But as a matter of fact, it is quite true that unless we have found the exact words to verbalize our own thoughts we can never be very sure of what our thoughts are; without words, our thoughts cannot be defined or stated in a clear and precise manner.4. “Malapropism” means the unintentional misuse of a word by confusing it with one that resembles it, such as human for humane, singularity for singleness. But the misuse of “imprison” is a different case. It is wronglychosen because the user has failed to recognize its connotation.5. human=of, characterizing, or relating to manhumane=characterized by kindness, mercy, sympathyThus: human action=action taken by man; humane action=merciful action; human killer=person that kills humans ; humane killer=that which kills but causes little pain6. sensitive, alert7. Those are words denoting notions which are existent only in specific culture, not universally shared by all cultures. English words difficult to be turned into Chinese: privacy, party, lobby (v.), etc. Chinese words difficult to be turned into English: 吹风会，粽子，五保户，etc.8. “We don’t have to look far afield to find evidence of bad carpentry.”“It is perhaps easier to be a good craftsman with wood and nails than a good craftsman with word s.”“A good carpenter is not distinguished by the number of his tools, but by the craftsmanship with which he uses them. So a good writer is not measured by the extent of his vocabulary, but by his skill in finding the ‘mot juste’, the word that will hit t he nail cleanly on the head.”Language Work:I. 1. shuffled/trudged 2. trudging 3. stroll 4. staggered 5. staggered 6. striding 7. strolled 8. strutted 9. sauntered/strolled 10. ramble/roam 11.loitered 12. meandering 13. roam 14. crept 15. prowled 16. toddle 17. roam 18. creeping 19. prowling 20. march 21. pace 22. patrolling 23. stalking 24. tread 25. tramped 26. stepped 27. plodded 28. A. prowled/strutted B. strolled/sauntered C. walked/crept D. marched/struttedII.1.SAY: speak, tell, declare, pronounce, express, state, argue, affirm, mention, allege, recite, repeat, rehearse2. SEE: behold, look at, glimpse, glance at, view, survey, contemplate, perceive, notice, observe, discern, distinguish, remark, comprehend, understand, know3. BEVERAGE: liquor, wine, beer, tea, coffee, milk drink, soft drink4. EXCITEMENT: agitation, perturbation, commotion, disturbance, tension, bustle, stir, flutter, sensation5. DELIGHT: joy, gladness, satisfaction, charm, rapture, ecstasy, pleasure, gratification6. SKILFUL: apt, ingenious, handy, ready, quick, smart, expert, capable, able, gifted, talented, dexterous, cleverIII. 1. clumsy----unskillful 2. deft----skillful 3. loose----vague 4. subtle----tricky 5. precise----accurate 6. shift----alteration 7. vague----ambiguous8. scrupulous----conscientious 9. ignorance----want of knowledge 10. disadvantages----drawbacks 11. cultivation----developing 12.mistaken----erroneous 13. unimportant----trivial 14. dark----dim 15. flexible----adaptable 16. fine----subtle 17. sentimental----emotional 18. essence----quintessence 19. coercion----compulsion 20. fascinating----absorbingIV. 1. craftsman 2. book/publication 3. artist 4. smile 5. contribution 6. law-breaker 7. eat 8. sleep 9. make 10. old 11. hit 12. get offV. 1. less 2. because/since/as 3. not 4. that 5. resistance 6. runners 7. solve 8. greater/more 9. that 10. without 11. achievement/feat 12. in 13. do 14. physical 15. those 16. few 17. cannot 18. the 19. with 20. not。

A Method for Crack Detection on a Concrete StructureYusuke FujitaYamaguchi University2–16–1Tokiwadai,Ube, Yamaguchi755–8611,Japan *********************.jpYoshihiro MitaniUbe National Collegeof Technology2–14–1Tokiwadai,Ube,Yamaguchi755–8555,JapanYoshihiko HamamotoYamaguchi University2–16–1Tokiwadai,Ube,Yamaguchi755–8611,JapanAbstractRecently,interest in automatic crack detection on con-crete structure images for non-destructive inspection has been increasing.In general,there are various noises such as irregularly illuminated conditions,shading,blemishes and divots in the concrete images.These lead to difficul-ties for automatic crack detection.This paper presents two pre-processings in order to remove such noises for crack detection.First,slight variations like irregularly illumi-nated conditions and shading are removed from concrete images by the subtraction pre-processing with the smoothed image.Secondly,a linefilter based on the Hessian matrix is used to emphasize line structures associated with cracks. Finally,thresholding processing is used to separate cracks from background.The performance of the proposed method is evaluated by ROC analysis with50real images.The ex-perimental results show that the proposed method is effec-tive for detecting cracks on noisy concrete images.1.IntroductionAn assessment of cracks may be crucial for reasons of safety and cost-effective maintenance of concrete struc-tures.The crack information can be used to adopt the appro-priate rehabilitation method tofix the cracked structure and prevent any catastrophic failure.However,crack detection on a concrete image is well known to be difficult because the conventional method involves a manual trace.In the trace, cracks are evaluated by the human operator.In practice, experience,skill level of the operator,concentration and re-liability of picture quality significantly influence the accu-racy of diagnosis about cracks,defect or failure of concrete structures.Therefore,automatic crack detection is highly desirable for efficiency and objectivity of crack assessment. In the past,several methods for automatic crack detection have been proposed[1,2,3].However,the segmentation of cracks from the concrete image is particularly difficult be-cause of the irregularities in crack shape and size,various blemishes and irregularly illuminated conditions.These of-ten lead to false detection.Thus,crack detection is required specifically for various cracks in complex background or in irregularly illuminated conditions.The purpose of our study is to detect cracks automati-cally from noisy concrete images.In this paper,we pro-pose two pre-processings for removal various factors such as blemishes or irregularly illuminated conditions on the concrete images.By ROC analysis with50noisy concrete images,we evaluate the proposed method in order to assess its robustness and accuracy.2.Proposed pre-processingsIn order to remove noises such as irregularly illuminated conditions,shading and a blemish,we propose two pre-processings for automatic crack detection.The proposed method consists of two pre-processings and one process-ing.First,the subtraction pre-processing is used to remove slight variation like irregularly illuminated conditions and shading.Secondly,the line emphasis pre-processing is used to emphasize line structures associated with cracks against blob structures such as blemish.After two pre-processings, thresholding processing is used to separate cracks from the background.The subtraction and line extraction pre-processings are described below.2.1.Subtraction pre-processingFigure1illustrates a removal of slight variation like ir-regularly illuminated conditions or shading.We subtract a smoothed image from an original image to obtain a sub-tracted image.Smoothing is used to remove a thin line structure associated with cracks.The smoothed image g() is obtained by convolving the medianfilter and the original image f()asg(x)=median f(x i)(x i∈R(x)),(1)Figure 1.Removal of slight variation like an irregularly illuminated condition,shading,or blemish.where x i is a pixel within a region R (x )around a pixel x .In the subtracted image,a slight variation caused by the irregularly illuminated condition or shading is removed.2.2.Line emphasis pre-processingThe line filter based on the Hessian matrix [4]is used in order to remove noises.The second derivative has been commonly used for line enhancement filtering.We use the Hessian matrix to measure similarity of a bright line that describes the second-order structures of local intensity vari-ations around each point of the image.The Hessian matrix of an image I (x )is given by∇2I (x )=I xx (x )I xy(x )I yx (x )I yy (x ) ,(2)where partial second derivatives of the image I (x )are rep-resented by expressions as I xx (x )=∂2∂x 2,I xy (x )=∂2∂x∂y ,I yx (x )=∂2∂y∂x ,and I yy (x )=∂2∂y 2.Let the eigenvalues of ∇2I (x )be λ1(x ),λ2(x )(λ1(x )>λ2(x )),and their cor-responding eigenvectors be e 1(x )and e 2(x ),respectively.Instead of computing the second order derivative of the im-age,we use the Gaussian convolution combined with the second derivative.The partial second derivatives of I (x )in Equation(2)can be replaced by the partial second deriva-tives of the Gaussian,I x i y j (x ;σf )=∂2∂x i ∂y jG (x ;σf )∗I (x )=d i dx i G (x ;σf )∗ d j dy jG (y ;σf )∗I (x ),(3)where i and j are non-negative integers satisfying i +j =2;G (x ;σf )is an isotropic Gaussian function with a standarddeviation σf defined as (1/2πσ2f )exp {(−x 2−y 2)/σ2f }.Using the Hessian matrix ∇2I (x ;σf )based on the second derivatives of Gaussian with σf ,the eigenvalues λ1(x ;σf )and λ2(x ;σf )can be turned to a specific width of bright line.When |λ2| |λ1|≈0,the structure should be re-garded as a line-like structure in the 2-D space.When the value of λ1is negative and |λ1|≈|λ2| 0,the struc-ture should be regarded as blob-like rather than line-like.Because noise components such as blemishes or divots typ-ically have blob-like shapes,it is important that the system possesses the ability to discriminate between line and blobs.When the value of λ1is positive,the structure involves con-cavity in the estimated line direction.The conditions of a bright line can be regarded as,λ1≈0,λ2 0.(4)Therefore,we derived a generalized measure of similarityto a line as,λ12=⎧⎪⎪⎪⎪⎪⎪⎪⎨⎪⎪⎪⎪⎪⎪⎪⎩|λ2| 1+λ1|λ2| =|λ2|+λ1if λ2≤λ1≤0|λ2|1−αλ1|λ2| =|λ2|−αλ1if λ2<0<λ1<|λ2|α0otherwise ,(5)where 0≤α≤1.Therefore,the filter responses tuned todifferent line widths can be combined in order to recover line structures of various widths.We normalize the filter re-sponses of each scale and then select the maximum response among the multiple scales.The multi-scale integration of the filter responses is defined byR (x )=max σiσ2iλ12(x ;σi ).(6)Let σi =s i −1σ1(i =1,2,...,n )be a discrete sample of σf ,where σ1is the minimum scale and s is a scale factor determining the sampling interval of σf .3Experimental ResultsWe used the receiver operating characteristic (ROC)analysis [5]to evaluate the performance of the proposed method.In this analysis,the different approaches are com-pared in terms of the sensitivity and the specificity.The sen-sitivity or true positive fraction (TPF)means the probability that cracks are detected correctly in pixel level.On the other hands,the specificity or false negative fraction (TNF)means the probability that backgrounds are correctly identified in pixel level.The choice of the threshold value influences both the sensitivity and the specificity.The ROC curve is the graphic representation of this reciprocal relationship be-tween the sensitivity and the specificity,calculated for allOriginal image Pre-processing thresholding Threshold [0,255]256binary images Comparison ROC curve Manual trace ?Traced imageCaluculate areas under the curve(A z )valueFigure 2.Flow of the pre-processing assess-ment by ROC analysis.possible threshold values.The vertical axis of the graph shows the sensitivity or TPF.The horizontal axis represents the false positive fraction (FPF =1−specificity).Each oper-ating point on the ROC curve represents the combination of the sensitivity and the specificity at a given threshold value.The closer to the upper left corner the ROC curve is,the pre-processing is better.We used the area under the curve (A z )value to estimate the performance of the pre-processing for crack detection.That is,the value of A z is a measure for the effectiveness of a pre-processing to be evaluated and is often used to make comparisons among some approaches.The major advantage of the approach of comparing a pre-processing by A z value is that this is done independently of decision criteria,thus eliminating the influence of the threshold value on the sensitivity and the specificity values.The performance of the proposed method is evaluated us-ing 50noisy concrete images with irregularly illuminated condition,varying shading,and various blemishes.These digitized images have 640×480pixels,approximately 0.1mm pixel size,and 8-bit gray levels.Note that our targets of detected cracks are over 0.2mm in width.In the evaluation,we compared the results by the proposed method with those by the approach without pre-processing,the approach with the subtraction pre-processing,and the approach with the line emphasis pre-processing.Here,we determined the size of the median fil-ter on the subtraction pre-processing and the parameters of the line emphasis processing according to our experiment.The size of the median filter was 21×21.The parameters for line emphasis filter were σ1=√2,s =√2,n =4,and α=0.25,respectively.Figure 2illustrates the assessment flow by the ROC analysis.The average and 95%confidence interval of A z valuesofFigure 3.An example of Comparison of four approachs by ROC curves.each approach for 50noisy concrete images were calculated as follows:Step 1Trace the cracks manually on the original image toobtain a traced image.It is used for comparison.Step 2Apply the pre-processing to an original concrete im-age.Step 3Threshold to separate cracks from background.Threshold values are changed from 0to 255,to obtain 256binary images as results of crack detection.Step 4Compare 256results detected automatically to thetraced image,respectively.The true positive fraction and false negative fraction are calculated as follows:T rue positive fraction =C cC t ,(7)F alse positive fraction =C eC t,(8)where C c is the number of crack pixels corresponding to crack pixels on traced image.C t is the number of crack pixels on truth image.C e is the number of back-ground pixels detected as crack pixels on truth image.Draw the ROC curve from 256relationship between the sensitivity and the specificity,and calculate the A z value.Step 5Repeat Steps from 1to 4for each of 50originalimages.Step 6Compute the average and 95%confidence intervalof the A z value.Table parison of four approaches by A z values.approach proposed method only subtraction only line emphasis no pre-processings.0.98130.90950.96920.8764A z0.9778,0.98480.8966,0.92230.9627,0.97590.8596,0.8932Upper average Lower 95%confidence interval(a)Original image (b)Manual tracing (c)Proposed method(d)Approach with subtraction (e)Approach with line emphasis (f)Approach without pre-processingsFigure parison of the results.Table 1shows the average and 95%confidence interval of A z values of each approach.From this,the subtraction pre-processing and line emphasis pre-processing lead to im-provement in crack detection from concrete surface images.Figure 3shows the difference of ROC curves among four approaches.It is clear that the ROC curve of the proposed method is rocated higher than the others.After the two pre-processings,we applied the Otsu’s thresholding technique [6]to detect cracks,and compared results among four pre-processing approaches.The Otsu’s thresholding technique selects a threshold based on integra-tion of the gray-scale histogram.Figure 4shows the results of crack detection.From the results,it is seen that the cracks are successfully detected by the proposed method.Furthermore,the result of the pro-posed method is closer to that by the manual tracing than those by the other approaches.4ConclusionIn order to improve the performance of crack detection on concrete images,we have proposed new pre-processings.The proposed method including the pre-processings is eval-uated by the ROC analysis.The experimental results show that the proposed method is effective for crack detection in practical situations.References[1] A.Ito Y .Aoki,and S.Hashimoto.Accurate extraction andmeasurement of fine cracks from concrete block surface im-age.IECON Proceedings (Industrial Electronics Confer-ence).[2]T.Yamaguchi,K.Suzuki,P.Hartono,and S.Hashimoto.Per-colation approach to image-based crack detection.Proceed-ings of the 7th international conference on Quality Control by Artificial Vision ,291-296,2005.[3]H.Nakamura,R.Sato.K.Kawamura,A.Miyamoto.Proposalof a crack pattern extraction method from digital images us-ing an interactive genetic algorithm.Japan Society of Civil Engineers ,60(742):115–131,September 2003(in Japanese).[4]Y .Sato,S.Nakajima,N.Shiraga,H.Atsumi,S.Yoshida,T.Koller,G.Gerig,and R.Kikinis.Three-dimensional multi-scale line filter for segmentation and visualization of curvi-linear structures in medical images.Medical Image Analysis ,2(2):143-168,1988.[5] A.R.van Erkel and P.M.T.Pattynama.Receiver operatingcharacteristic (roc)analysis:Basic principles and applications in radiology.European Journal of Radiology ,27(2):88-94,May 1998.[6]N.Otsu.Threshold selection method from gray-level his-tograms.IEEE Trans.Syst.Man Cybern ,SMC-9(1):62-66,1979.。

DCM2005Preliminary VersionAbstract Effective ModelsUdi Boker1,2School of Computer ScienceTel Aviv UniversityTel Aviv69978,IsraelNachum Dershowitz3School of Computer ScienceTel Aviv UniversityTel Aviv69978,IsraelAbstractWe modify Gurevich’s notion of abstract machine so as to encompass computational models,that is,sets of machines that share the same domain.We also add an effec-tiveness requirement.The resultant class of“Effective Models”includes all known Turing-complete state-transition models,operating over any countable domain.Key words:Computational models,Turing machines,ASM,Abstract State Machines,Effectiveness1Sequential ProceduresWefirst define“sequential procedures”,along the lines of the“sequential algorithms”of[3].These are abstract state transition systems,whose states are algebras.Definition1.1(States)•A state is a structure(algebra)s over a(finite-arity)vocabulary F,that is, a domain(nonempty set of elements)D together with interpretations[[f]]s over D of the function names f∈F.•A location of vocabulary F over a domain D is a pair,denoted f(a),where f is a k-ary function name in F and a∈D k.1This work was carried out in partial fulfillment of the requirements for the Ph.D.degree of thefirst author.2Email:udiboker@tau.ac.il3Email:nachumd@tau.ac.ilThis is a preliminary version.Thefinal version will be published inElectronic Notes in Theoretical Computer ScienceURL:www.elsevier.nl/locate/entcs•The value of a location f(a)in a state s,denoted[[f(a)]]s,is the domain element[[f]]s(a).•We sometimes use a term f(t1,...,t k)to refer to the location f([[t1]]s,...,[[t k]]s).•Two states s and s over vocabulary F with the same domain coincide over a set T of F-terms if[[t]]s=[[t]]s for all terms t∈T.•An update of location l over domain D is a pair,denoted l:=v,where v∈D.•The modification of a state s into another state s over the same vocabulary and domain is∆(s,s )={l:=v |[[l]]s=[[l]]s =v }.•A mappingρ(s)of state s over vocabulary F and domain D via injection ρ:D→D is a state s of vocabulary F over D ,such thatρ([[f(a)]]s)= [[f(ρ(a))]]s for every location f(a)of s.•Two states s and s over the same vocabulary with domains D and D , respectively,are isomorphic if there is a bijectionπ:D↔D ,such that s =π(s).A“sequential procedure”is like Gurevich’s[3]“sequential algorithm”,with two modifications for computing a specific function,rather than expressing an abstract algorithm:the procedure vocabulary includes special constants“In”and“Out”;there is a single initial state,up to changes in In.Definition1.2(Sequential Procedures)•A sequential procedure A is a tuple F,In,Out,D,S,S0,τ ,where:F is afinite vocabulary;In and Out are nullary function names in F;D,the procedure domain,is a domain;S,its states,is a collection of structures of vocabulary F,closed under isomorphism;S0,the initial states,is a subset of S over the domain D,containing equal states up to changes in the value of In(often referred to as a single state s0);andτ:S→S,the transition function,such that:·Domain invariance.The domain of s andτ(s)is the same for every state s∈S.·Isomorphism preservation.The transition function preserves isomor-phism.Meaning,if states s and s are isomorphic via a bijectionπ,then τ(s)andτ(s )are also isomorphic viaπ.That is,τ(π(s))=π(τ(s)).·Bounded exploration.There exists afinite set T of“critical”terms, such that∆(s,τ(s))=∆(s ,τ(s ))if s and s coincide over T.Tuple elements of a procedure A are indexed F A,τA,etc.•A run of a procedure A is afinite or infinite sequence s0;τs1;τs2;τ···,where s0is an initial state and every s i+1=τA(s i).•A run s0;τs1;τs2;τ···terminates if it isfinite or if s i=s i+1from some point on.•The terminating state of a terminating run s0;τs1;τs2;τ···is2its last state if it is finite,or its stable state if it is infinite.If there is a terminating run beginning with state s and terminating in state s ,we write s ;!τs .•The extensionality of a sequential procedure A over domain D is the partial function f :D →D ,such that f (x )=[[Out ]]s whenever there’s a run s ;!τs with [[In ]]s =x ,and is undefined otherwise.Domain invariance simply ensures that a specific “run”of the procedure is over a specific domain.The isomorphism preservation reflects the fact that we are working at a fixed level of abstraction.See [3,p.89].The bounded-exploration constraint is required to ensure that the behavior of the procedure is effective.This reflects the informal assumption that the program of an algorithm can be given by a finite text [3,p.90].2Programmable MachinesThe transition function of a “programmable machine”is given by a finite “flat program”:Definition 2.1(Programmable Machines)•A flat program P of vocabulary F has the following syntax:if x 11.=y 11and x 12.=y 12and ...x 1k 1.=y 1k 1then l 1:=v 1if x 21.=y 21and x 22.=y 22and ...x 2k 2.=y 2k 2then l 2:=v 2...if x n 1.=y n 1and x n 2.=y n 2and ...x nk n .=y nk nthen l n :=v n where each .=is either ‘=’or ‘=’,n,k 1,...,k n ∈N ,and all the x ij ,y ij ,l i ,and v i are F -terms.•Each line of the program is called a rule .•The activation of a flat program P on an F -structure s ,denoted P (s ),is a set of updates {l :=v |if p then l :=v ∈P,[[p ]]s }(under the standard interpretation of =,=,and conjunction),or the empty set ∅if the above set includes two values for the same location.•A programmable machine is a tuple F ,In ,Out ,D,S ,S 0,P ,where all but the last component is as in a sequential procedure (Definition 1.2),and P is a flat program of F .•The run of a programmable machine and its extensionality are defined as for sequential procedures (Definition 1.2),where the transition function τis given by τ(s )=s ∈S such that ∆(s,s )=P (s ).To make flat programs more readable,we combine rules,as in3%commentif cond-1stat-1stat-2elsestat-3Analogous to the the main lemma of[3],one can show that every program-mable machine is a sequential procedure,and every sequential procedure is a programmable machine.In contradistinction to Abstract Sequential Machines(ASMs),we do not have built in equality,booleans,or an undefined in the definition of procedures: The equality notion is not presumed in the procedure’s initial state,nor can it be a part of the initial state of an“effective procedure”,as defined below. Rather,the transition function must be programmed to perform any needed equality checks.Boolean constants and connectives may be defined like any other constant or function.Instead of a special term for undefined values,a default domain value may be used explicitly.3Effective ModelsWe define an“effective procedure”as a sequential procedure satisfying an “initial-data”postulate(Axiom3.3below).This postulate states that the procedures may have onlyfinite initial data in addition to the domain repre-sentation(“base structure”).An“effective model”is,then,any set of effective procedures that share the same domain representation.We formalize thefiniteness of the initial data by allowing the initial state to contain an“almost-constant structure”.Since we are heading for a char-acterization of effectiveness,the domain over which the procedure actually operates should have countably many elements,which have to be nameable. Hence,without loss of generality,one may assume that naming is via terms. Definition3.1(Almost-Constant and Base Structures)•A structure S is almost constant if all but afinite number of locations have the same value.•A structure S offinite vocabulary F over a domain D is a base structure if all the domain elements are the value of a unique F-term.That is,for every element e∈D there exists a unique F-term t such that[[t]]S=e.•A structure S of vocabulary F over domain D is the union of structures S and S of vocabularies F and F ,respectively,over D,denoted S=S S , if F=F F ,[[l]]S=[[l]]S for every location l of S ,and[[l]]S=[[l]]S for every location l of S .A base structure is isomorphic to the standard free term algebra(Herbrand universe)of its vocabulary.4Proposition3.2Let S be a base structure over vocabulary G and domain D. Then:•Vocabulary G has at least one nullary function.•Domain D is countable.•Every domain element is the value of a unique location of S.Axiom3.3(Initial Data)The procedure’s initial states consist of an infi-nite base structure and an almost-constant structure.That is,for some infinite base structure BS and almost-constant structure AS,and for every initial state s0,we have s0=BS AS {In}for some In.Definition3.4(Effective Procedures and Models)•An effective procedure A is a sequential procedure satisfying the initial-data postulate.An effective procedure is,accordingly,a tuple F,In,Out,D,S,S0,τ,BS,AS ,adding a base structure BS and an almost-constant structure AS to the sequential procedure tuple,defined in Defini-tion1.2.•An effective model E is a set of effective procedures that share the same base structure.That is,BS A=BS B for all effective procedures A,B∈E.A computational model might have some predefined complex operations,as in a RAM model with built-in integer multiplication.Viewing such a model as a sequential algorithm allows the initial state to include these complex functions as oracles[3].Since we are demanding effectiveness,we cannot allow arbitrary functions as oracles,and force the initial state to include only finite data over and above the domain representation(Axiom3.3).Hence,the view of the model at the required abstraction level is accomplished by“big steps”,which may employ complex functions,while these complex functions are implemented by afinite sequence of“small steps”behind the scenes.That is,(the extensionality of)an effective procedure may be included(as an oracle) in the initial states of other effective procedures.(Cf.the“turbo”steps of[2].) 4Effective Includes ComputableTuring machines,and other computational methods,can be shown to be ef-fective.We demonstrate below how Turing machines and counter machines can be described by effective models.4.1Turing Machines.We consider Turing machines(TM)with two-way infinite tapes.The tape alphabet is{0,1}.The two edges of the tape are marked by a special$ sign.As usual,the state(instantaneous description)of a Turing machine is Left,q,Right ,where Left is afinite string containing the tape section left of the reading head,q is the internal state of the machine,and Right is afinite5string with the tape section to the right to the read head.The read head points to thefirst character of the Right string.TMs can be described by the following effective model E:Domain:Finite strings ending with a$sign.That is the domain D= {0,1}∗$.Base structure:Constructors for thefinite strings(name/arity):$/0, Cons0/1,and Cons1/1.Almost-constant structure:•Input and Output(nullary functions):In,Out.The value of In at the initial state is the content of the tape,as a string over{0,1}∗ending with a$sign.•Constants for the alphabet characters and TM-states(nullary):0,1,q0, q1,...,q k.Their initial value is irrelevant,as long it is a different value for each constant.•Variables to keep the current status of the Turing machine(nullary):Left, Right,and q.Their initial values are:Left=$,Right=$,and q=q0.•Functions to examine the tape(unary functions):Head and Tail.Their initial value,at all locations,is$.Transition function:For each Turing machine m∈TM,define an effective procedure m ∈E via aflat program looking like this:if q=q_0%TM’s state q_0if Head(Right)=0%write1,move right,switch to q_3Left:=Cons_1(Left)Right:=Tail(Right)q:=q_3%Internal operationsTail(Cons_1(Left)):=LeftHead(Cons_1(Left)):=1if Head(Right)=1%write0,move left,switch to q_1Left:=Tail(Left)Right:=Cons_0(Right)q:=q_1%Internal operationsTail(Cons_0(Right)):=RightHead(Cons_0(Left)):=0if q=q_1%TM’s state q_1...if q=q_k%the halting stateOut:=Right6The updates for Head and Tail are bookkeeping operations that are really part of the“behind-the-scenes”small steps.The procedure also requires some initialization,in order tofill the internal functions Head and Tail with their values for all strings up to the given input string.It sequentially enumerates all strings,assigning their Head and Tail values,until encountering the input string.The following internal variables (nullary functions)are used in the initialization(Name=initial value):New= $,Backward=0,Forward=1;AddDigit=0,and Direction=$.%Sequentially constructing the Left variable%until it equals to the input In,for filling%the values of Head and Tail.%The enumeration is$,0$,1$,00$,01$,...if Left=In%FinishedRight:=LeftLeft:=$else%Keep enumeratingif Direction=New%default valif Head(Left)=$%$->0$Left:=Cons_0(Left)Head(Cons_0(Left)):=0Tail(Cons_0(Left)):=Leftif Head(Left)=0%e.g.110$->111$Left:=Cons_1(Tail(Left))Head(Cons_1(Tail(Left)):=1Tail(Cons_1(Tail(Left)):=Tail(Left)if Head(Left)=1%01$->10$;11$->000$Direction:=BackwardLeft:=Tail(Left)Right:=Cons_0(Right)if Direction=Backwardif Head(Left)=$%add rightmost digitDirection:=ForwardAddDigit:=Trueif Head(Left)=0%change to1Left:=Cons_1(Tail(Left))Direction:=Forwardif Head(Left)=1%keep backwardsLeft:=Tail(Left)Right:=Cons_0(Right)if Direction=Forward%Gather right0sif Head(Right)=$%finished gatheringDirection:=Newif AddDigit=1Left:=Cons_0(Left)Head(Cons_0(Left)):=0Tail(Cons_0(Left)):=Left7AddDigit=0elseLeft:=Cons_0(Left)Right:=Tail(Right)Head(Cons_0(Left)):=0Tail(Cons_0(Left)):=Left4.2Counter Machines.Counter machines(CM)can be described by the following effective model E:The domain is the natural numbers N.The base structure consists of a nullary function Zero and a unary function Succ,interpreted as the reg-ular successor over N.The almost-constant structure has the vocabulary (name/arity):Out/0,CurrentLine/0,P red/1,Next/1,Reg0,...,Reg n/0, and Line1,...,Line k/0.Its initial data are T rue=1,Line i=i,and all other locations are0.The same structure applies to all machines,except for the number of registers(Reg i)and the number of lines(Line i).For every counter machine m∈CM,define an effective procedure m ∈E with the followingflat program:%Initialization:fill the values of the%predecessor function up to the value%of the inputif CurrentLine=Zeroif Next=Succ(In)CurrentLine:=Line_1elsePred(Succ(Next)):=NextNext:=Succ(Next)%Simulate the counter-machine program.%The values of a,b,c and d are as in%the CM-program lines.if CurrentLine=Line_1Reg_a:=Succ(Reg_a)%or Pred(Reg_a)Pred(Succ(Reg_a)):=Reg_aif Reg_b=ZeroCurrentLine:=celseCurrentLine:=dif CurrentLine=Line_2...%Always:Out:=Reg_085DiscussionIn[3],Gurevich proved that any algorithm satisfying his postulates can be represented by an Abstract State Machine.But an ASM is designed to be “abstract”,so is defined on top of an arbitrary structure that may contain non-effective functions.Hence,it may compute non-effective functions.We have adopted Gurevich’s postulates,but added an additional postulate(Axiom3.3) for effectivity:an algorithm’s initial state may contain onlyfinite data in addition to the domain representation.Different runs of the same procedure share the same initial data,except for the input;different procedures of the same model share a base structure.Here,we showed that Turing machines and counter machines are effective models.In[1],we prove theflip side,namely that Turing machines can sim-ulate all effective models.To cover hypercomputational models,one would need to relax the effectivity axiom or the bounded exploration requirement. References[1]Udi Boker and Nachum Dershowitz,A formalization of the Church-TuringThesis,in preparation.[2]N.G.Fruja and R.F.St¨a rk.The hidden computation steps of Turbo AbstractState Machines.In E.B¨o rger,A.Gargantini,and E.Riccobene,editors,Abstract State Machines—Advances in Theory and Applications,10th International Workshop,ASM2003,Taormina,Italy,pages244–262.Springer-Verlag,Lecture Notes in Computer Science2589,2003.[3]Yuri Gurevich.Sequential abstract state machines capture sequential algorithms.ACM Transactions on Computational Logic,1:77–111,2000.9。

拟南芥成花途径拟南芥成花途径摘要成花转变是⼀个复杂的过程，不仅是形态上的变化，⽽且包括在花芽分化前发⽣的⼀系列复杂的⽣理⽣化变化，通过感受外部环境因⼦（包括光周期、温度和GA等）变化，经内源因⼦（包括营养状况和年龄发育阶段等）作⽤，最终促进茎尖分⽣组织分化形成花或花序，保证⽣殖最优化。

成花过程是⼀个复杂的调控⽹络，拟南芥中⾄少有7条成花调控途径，其中包括了⼀些编码不同类型蛋⽩的“成花整合因⼦”，它们通过整合各个途径的信号调控成花时间，例如能够快速促进花发育的FLOWERING LOCUS T (FT)和SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 (SOC1)。

关键词：光周期途径；春化途径；⾃主途径；年龄途径；⾚霉素途径；常温途径；糖类途径⽬前拟南芥中⾄少有7条主要的信号途径参与调控，即响应⽇照长度和感应光质调控开花的光周期途径（photoperiod pathway），低温促进成花的春化途径（vernalization pathway），⾚霉素调控植物成花的⾚霉素途径（GA pathway），与⾚霉素和光周期不相关⽽依赖⾃⾝发育状况的⾃主途径（autonomous pathway），响应温度的常温途径（ambient temperature pathway），通过增加植物的年龄调控成花的年龄途径（age pathway）以及通过植物体内碳⽔化合物代谢状态调控成花的糖类途径（Trehalose-6-Phosphatepathway）。

图1-1. 拟南芥开花途径概览（Fabio et al.,2013;Khan et al.,2013）Figure 1-1. Overview of ?owering pathways in Arabidopsis（Fabio et al.,2013;Khan et al.,2013）光周期途径和昼夜节律钟（photoperiod pathwayand the circadian clock）拟南芥是长⽇照植物，在长⽇条件下能够促进成花，在短⽇条件下则抑制成花。

Cognitive Changes Associated with AgingAndrew E. Scharlach and Barrie RobinsonIntroduction1.Research on the human brain has documented dramatic decreases in brain size and efficiency throughout our lives, beginning virtually from the time of birth. Yet, in spite of these anatomical and physiological declines, studies have found evidence of only limited decrements in actual intellectual functioning associated with the aging process. This section examines some of these known decrements in two fundamental domains of cognitive functioning: (1) intelligence, and (2) learning and memory.2.The fact that quite a lot of older persons experience virtually no functional impairment despite their cognitive limitations is a testimony to the redundancy built into the human brain, as well as the ability of humans to find ways to compensate for potential cognitive limitations. It also reflects the fact that intellectual ability is only one of many factors affecting functioning in later life. Ultimately, intellect may be considerably less important than are self-care ability and social competence in determining an older person’s ability to function independently and competently, and to live a rich, rewarding life.Intelligence3.Intelligence generally can be thought of as including a range of abilities that allow us to make sense of our experiences: the ability to comprehend new information, the ability to think abstractly, the ability to make rational decisions, spatial ability, numerical ability, verbal fluency, etc. Some abilities (e.g., the ability to think abstractly) are heavily biologically determined and are relatively independent of particular applications, reflecting what has been called “fluid intelligence.” Other intellectual abilities (e.g., verbal fluency) are more apt to reflect the knowledge and skills a person has gained through life experience, or “crystallized intelligence.”4.Intelligence tests have demonstrated a pattern of age-related changes in intellectual functioning typically beginning afte r the age of 60. This “classic aging pattern” involves somewhat poorer performance on tests of fluid intelligence, but little or no difference on tests of crystallized intelligence. It should be noted, however, that there is a great deal of variability in the test scores of older adults, with some older persons actually doing better than some younger persons. Moreover, older adults’ intellectual functioning can be improved significantly with training and practice, although improvements generally are less than those experienced by younger persons with the same amount of training.5.The fact that older persons seem to perform more poorly on tests of fluid intelligence is due in part to reduced efficiency of nerve transmission in the brain, resulting in slower information processing and greater loss of information during transmission. However, performance decrements may also be due to a variety of non-cognitive factors, including impairments in motor ability and sensation. Slower motor performance can signifi cantly reduce an older person’s ability to respond ontests that require fine hand movements (e.g., filling in the proper rectangle on an answer sheet). Sensory deficits associated with aging, for example, can result in perceptual inaccuracies, requiring the aging mind to commit more attention and cognitive effort to comprehending sensory input and reducing its capacity to quickly process new information.6.Other factors affecting cognitive performance in older adults are only indirectly related to the aging process itself. For example, older persons typically have fewer years of education. They also are likely not to have as much experience taking intelligence tests as do younger persons who grew up in an era of widespread intelligence testing, resulting in reduced familiarity and increased test anxiety for older test takers. Moreover, the content of these tests often is less meaningful for older persons, reducing their motivation for committing precious time and energy on difficult test items that have little personal meaning.7.When making decisions, older persons have been found to sacrifice speed for accuracy, rejecting quick, simplistic solutions to problems and preferring to work slowly, examining issues from a variety of perspectives before selecting a response. Finally, many of the health problems which are more common in later life (e.g., cardiovascular problems) can significantly affect cognitive functioning as well as test-taking ability.8.Not all cognitive changes in later life are negative, however. Older persons typically exhibit greater experience-based knowledge, increased accuracy, better judgment, and generally improved ability to handle familiar tasks than younger persons. Such applied knowledge, or wisdom, may in fact be considerably more important to one’s ability to accomplish most tasks of day-to-day life than are the abstract abilities tapped by intelligence tests.9.Even when physical or cognitive competencies are affected by the aging process, older adults often are able to develop strategies for compensating partially or totally. For example, older typists have been found to type as quickly and as accurately as younger typists even though they are unable to move their fingers as fast, because they have developed a better ability to anticipate upcoming words and locate the proper keys on the typewriter. In general, older adults can perform about as well as younger persons on tasks which provide sufficient opportunity to compensate for slower physical and cognitive functioning.Learning and Memory10.Most persons experience a modest increase in memory problems as they get older, particularly with regard to the ability to remember relatively recent experiences. Decrements are found both in the ability to accumulate new information and in the ability to retrieve existing information from memory storage，although there is little decline in the ability to store new information once it is learned.11.The process of learning new information and encoding it for storage requires more time as individuals get older, because of the reduced efficiency of neural transmission and because of sensory deficits that limit one’s ability to quickly and accurately perceive information to be learned (as discussed above). In fast-movingday-to-day experiences, this may prevent individual experiences (e.g., the name of someone to whom one is introduced) from receiving the attention needed for complete encoding into secondary memory. In addition, the extensive life experience of older persons makes it more likely that new information will not adequately be distinguishable from previous learning (e.g., the names of other similar people one has met over the years), making it difficult to establish unique cues and linkages for new experiences.12.Older persons also experience decrements in their ability to retrieve information once it is stored. In part, this is because of the difficulty identifying just the right piece of information from the vast store of information they have accumulated over a lifetime of experiences. This can be particularly difficult when the new information resembles previously learned information (e.g., when one is trying to recall a phone number from the thousands of phone numbers that have been learned over a lifetime). Consequently, older persons tend to do considerably worse than younger persons on tests of free recall, where they are asked to retrieve learned information but given only minimal cues. However, few decrements are found when older adults are given sufficient orienting parameters to limit the scope of the search, or are asked to select the correct answer from among a small number of options (e.g., on a multiple choice test).13.Older persons seem to have better memory for certain events that occurred in the distant past than for recent experiences. To a large extent, this is because the distant events that are remembered are those which either have special personal significance (e.g., the birth of a child, the end of World War II) or are so unique that they are not affected by subsequent experiences (e.g., childhood occurrences). Such experiences are apt to have been rehearsed mentally numerous times throughout one’s life, increasing their familiarity and making them easier to recall than are mundane aspects of on e’s day-to-day life. In addition, it is considerably more difficult to validate the accuracy of information from the distant past than it is to validate more recent information, so that errors in remembering recent events usually are more obvious than are errors regarding distant events.14.Finally, it is important to note that cognitive processes such as learning, memory, and intellectual functioning are extremely responsive to a person’s physical and psychological state. Physical illnesses and medications can affect neuronal function and also reduce the energy available for cognitive processes. Depression and other emotional conditions that involve impaired self-esteem and reduced confidence in one’s own abilities can significantly impair one’s motivati on for learning and remembering new information. Among depressed older adults, for example, memory complaints can increase and memory performance can decline even in persons who do not have any actual impairment in cognitive functioning or learning ability. Moreover, older adults who have adopted the popular stereotype that forgetfulness is inevitable in old age may experience increased anxiety and reduced self-confidence when confronted with normal memory tasks, resulting in memory problems they would not otherwise have had.与衰老相关的认知变化安德鲁E. Scharlach和巴里·鲁宾逊的介绍1。

Unit 1 hit the nail on the head 恰到好处Have you ever watch‎e d a clums‎y man hamme‎r ing a nail into a box? He hits it first‎to one side, then to anoth‎e r, perha‎p s knock‎i ng it over compl ‎e t ely‎,so that in the end he only gets half of it into the wood. A skill ‎f u l carpe‎n ter, on the other‎hand, will drive‎the nail with a few firm, deft blows‎,hitti‎n g it each time squar‎e ly on the head. So with langu‎a ge; the good craft‎s man will choos‎e words‎that drive‎home his point‎firml‎y and exact‎l y. A word that is more or less right‎,a loose‎phras‎e, an ambig‎u ous expre‎s sion‎,a vague‎adjec‎t ive（模糊的形容‎词）, will not satis‎f y a write ‎r who aims at clean‎Engli‎s h. He will try alway‎s to get the word that is compl‎e tely‎right‎for his purpo‎s e.你见过一个‎笨手笨脚的‎男人往箱子‎上钉钉子吗‎？只见他左敲‎敲，右敲敲，说不准还会‎将整个钉子‎锤翻，结果敲来敲‎去到头来只‎敲进了半截‎。

ICP-MS : The Ultimate GC DetectorMina Tanoshima, Steve Wilbur, and Emmett SoffeyAgilent Technologies Inc . 34th International Symposium on Capillary Chromatography 2010ExperimentalIntroductionGas chromatography (GC) is widely used for the speciation and detection of volatile organic compounds in many applications and industries. There are many detectors for GC, such as PFPD/FPD ((pulsed) flame photometric detector) or SCD (Sulfur chemiluminescence detector) for sulfur, NPD (nitrogen/phosphorus detector) for nitrogen and phosphorus and ECD (electron capture detector) for the halogens. GC is also combined with a mass spectrometer or mass selective detector (MS or MSD), both with single quadrupole or triple-quad (QQQ). However, none of these detectors is capable of providing universal, element specific quantification in the manner of ICP-MS. ICP-MS provides a unique combination of rapid multi-element/isotope analysis, with very high sensitivity.Results and DiscussionConclusionsFigure 1. Agilent’s ICP -MS coupled to the Agilent’s 7890A GC.InstrumentationAgilent’s 7890A GC and Agilent’s 7700x ICP -MS were connected using the new GC interface kit provided by Agilent (As shown in Figure 1.) to evaluate these three analyses; 1)Organo-tin, 2) Polybrominated Diphenyl Ether (PBDE), and 3) Sulfur species in diesel. This GC interface connects the two instruments via a passivated, heated Sulfinert ®tube between the GC column and the tip of the ICP injector using a special torch with a heated injector to maintain constant high temperature and inertness. The schematic is shown in Figure 2.The use of ICP-MS as a GC detector significantly extends GC capability and expands its application. With a well-designed GC / ICP-MS interface featuring hightemperature and inertness, Organo-tin , PBDE and sulfur compounds in diesel were successfully analyzed.Those results demonstrated benefit of ICP-MS’ ultimate detection limit and multi element analysis capability.1) Organo-tin analysisThe toxic effects of organo-tin compounds in the environment are well known and research has begun to include matrices with human health implications, such as seafood, manufactured products, and human blood samples. In this study, a mixed organo-tin standard was analyzed. The analysis was completed in less than 12 minutes achieving detection limit of 5.9ppt for tributyl tin (TBT).GC Injection Splitless 1ulColumnDB-5MS (5m x 0.25 mm x 0.25um film thickness)Oven Program80℃(1min), 20℃/min -> 320℃(5min)Carrier gas He at 7mL/min Inlet Temp 260 deg C Transfer line temp250 deg CICP injector temp 280 deg CICP-MS ICP-MS model 7700x RF Power 1250 W Sample Depth 7 mm Carrier gas 0.61 L/min Aux Gas 1.5 L/min Additional Gas No Monitored mass (m/z)79, 81GC Injection Splitless 1ulColumn HP-5 (30m x 0.32mm i.d. x 0.25 um film thickness)Oven Program70 deg(1min) ~ 30deg/min ~190deg (0min) ~ 15deg/min ~ 270deg (4min)Carrier gas He at 2mL/min Inlet Temp 290 deg C Transfer line temp 250 deg C ICP injector temp250 deg CICP-MS ICP-MS model 7700xRF Power 1200 WSample Depth 8 mm Carrier gas 0.80 L/min Aux Gas 1.5 L/min Additional GasNoMonitored mass (m/z)118,1202) Polybrominated Diphenyl Ether (PBDE) analysisPBDEs are widely used flame retardants added to many common household products, such as mattresses and furniture, and electronic devices. However their similarity in structure to PCBs and dioxins has raised concerns about health risks associated with their use. For this study, a PBDE mix(CIL Predominant Congener Mixture EO-5103) containing 14 different PBDEs were analyzed. (Chromatogram is shown in Figure 4.) All the PBDEs were separated successfully with good sensitivity, even for the difficult #209 (decaBDE) congener, which is thermally labile anddecomposes easily during GC separation. The detection limit was150ppt for Deca BDE .3) Sulfur analysis in diesel fuelSulfur in motor fuels has been implicated in global warming and acid rain. It is also a catalyst poison for automobile catalytic converters and refinery catalytic crackers. Reducing total sulfur in motor fuels has become a critical air pollution control goal worldwide. Figure5 show the chromatogram for low sulfur in diesel samples (NIST 2724B).GC and ICP-MS operating parameters are shown in Table 3.Figure 2. Schematic diagram for Agilent’s GC -MS interface for the 7890GC/7700 ICP-MSRT (min)C o u n tFull Time Range EIC (mass 79)C o u n tFull Time Range EIC (mass 120):RT (min)Figure 4. Chromatogram of mixed PBDE standard: 25ppb each compound except #138 (37.5ppb) and #209 (100ppb)Figure 3. Chromatogram of 10ppb Organo-tin standard. The samples was delivaized beforehand. Table 1. Method parameters for the separation of Organo-tin using the GC with ICP-MS detection.(1) 2, 2’,4-TriBDE (BDE –17)(2) 2, 4’,4-TriBDE (BDE –28)(3) 2, 3’,4’,6-TetraBDE (BDE –71)(4) 2, 2’,4,4’-TetraBDE (BDE –47)(5) 2, 3’,4,4’-TetraBDE (BDE –66) (6) 2, 2’,4,4’,6-PentaBDE (BDE –100) (7) 2, 2’,4,4’-5-PentaBDE (BDE –99) (8) 2, 2’,3,4,4’-PentaBDE (BDE –85) (9) 2, 2’,4,4’,5,6’-HexaBDE (BDE –154) (10) 2, 2’,4,4’,5,5’-HexaBDE (BDE –153)(11) 2, 2’,3,4,4’,5’-HexaBDE (BDE –138) (12) 2, 2’,3,4,4’,5’,6-heptaBDE (BDE –183) (13) 2, 3,3’,4,4’,5’,6’-HeptaBDE (BDE –190) (14) DecaBDE (BDE –209) Table 2. Method parameters for the separation of PBDEs using the GC with ICP-MS detection.GC Injection Split 1:50 1ulColumn HP-5 (30m x 0.32mm i.d. x 0.25 um film thickness)Oven Program 40deG(4min) ~ 20deG/min ~250deG (1min)Carrier gas He at 2.5mL/min Inlet Temp 250 degC Transfer line temp 250 degC ICP injector temp260 degCICP-MS ICP-MS model 7700x RF Power 1550 W Sample Depth 8 mm Carrier gas 0.80 L/min Aux Gas 1.5 L/min Additional Gas No Monitored mass (m/z)118,120Table 3. GC and ICP-MS operating parameters.Figure 5. Carbon and sulfur extracted ion chromatograms for NIST 2724B low sulfur.RT (sec)C o u n t。

u5u6作文构思英语五年级The art of essay writing is a fundamental skill that students in grade 5 must develop in order to excel in their academic pursuits. An essay is a structured piece of writing that allows individuals to express their thoughts, ideas, and perspectives on a given topic. Crafting a well-written essay requires a combination of critical thinking, effective communication, and attention to detail.In the case of a grade 5 essay on the topic of "u5u6 Essay Composition in English," the student must demonstrate their understanding of the subject matter and their ability to organize their thoughts in a coherent and engaging manner. The essay should be structured with a clear introduction, body, and conclusion, each serving a specific purpose in the overall narrative.The introduction should serve as a hook, capturing the reader's attention and providing a brief overview of the topic. It should set the stage for the rest of the essay, outlining the key points that will be explored in the body paragraphs. The introduction should be concise and engaging, drawing the reader in and setting the tone forthe rest of the essay.The body paragraphs of the essay should delve deeper into the topic, exploring the various aspects of "u5u6 Essay Composition in English" in a structured and logical manner. Each paragraph should focus on a specific point or idea, with supporting evidence and examples to reinforce the argument. The paragraphs should flow seamlessly from one to the next, creating a cohesive and coherent narrative.One of the key aspects of a successful grade 5 essay is the ability to effectively communicate the writer's ideas and perspectives. This requires a strong command of the English language, including proper grammar, spelling, and vocabulary. The essay should be written in a clear and concise manner, with a focus on conveying the information in a way that is easily understood by the reader.Another important aspect of the essay is the inclusion of relevant and well-researched information. The student should draw upon a variety of sources, including textbooks, online resources, and other scholarly materials, to support their arguments and provide a comprehensive understanding of the topic. The essay should demonstrate the student's ability to synthesize information from multiple sources and present it in a coherent and compelling manner.Finally, the conclusion of the essay should serve as a summary of thekey points discussed throughout the body paragraphs. It should restate the main argument or thesis, and provide a final reflection on the significance of the topic. The conclusion should leave the reader with a clear understanding of the essay's main points and the student's overall perspective on the subject matter.In conclusion, the "u5u6 Essay Composition in English" assignment for grade 5 students is a valuable opportunity for students to develop their writing skills and demonstrate their understanding of a complex topic. By crafting a well-structured, well-written, and well-researched essay, students can showcase their critical thinking abilities and their ability to effectively communicate their ideas to a wider audience.。

Incomplete Contracts and the Product CycleBy P OL A NTRA`S*I present a model in which the incomplete nature of contracts governing interna-tional transactions limits the extent to which the production process can be frag-mented across borders.Because of contractual frictions,goods are initially manufactured in the same country where product development takes place.Only when the good becomes sufficiently standardized is the manufacturing stage of production shifted to a low-wage foreign location.Solving for the optimal organi-zational structure,I develop a new version of the product cycle hypothesis in which manufacturing is shifted abroadfirst withinfirm boundaries,and only at a later stage to independent foreignfirms.(JEL D23,F12,F14,F21,F23,L22,L33)In an enormously influential article,Ray-mond Vernon(1966)described a natural life cycle for the typical commodity.Most new goods,he argued,are initially manufactured in the country where they arefirst developed,with the bulk of innovations occurring in the indus-trialized North.Only when the appropriate de-signs have been worked out,and the production techniques have been standardized,is the locus of production shifted to the less developed South,where wages are lower.Vernon empha-sized the role of multinationalfirms in the in-ternational transfer of technology.In his formulation of a product’s life cycle,the shift of production to the South is a profit-maximizing decision from the point of view of the innovat-ingfirm.The“product cycle hypothesis”soon gave rise to an extensive empirical literature that searched for evidence of the patterns suggested by Vernon.1The picture emerging from this literature turned out to be much richer than Vernon originally envisioned.The evidence in-deed supports the existence of product cycles, but it has become clear that foreign direct in-vestment by multinationalfirms is not the only vehicle of production transfer to the South.The literature has identified several instances in which technologies have been transferred to the South through licensing,subcontracting,and other similar arm’s length arrangements.More interestingly,several studies have pointed out that the choice between intrafirm and market transactions is significantly affected by both the degree of standardization of the technology and by the resources devoted to product develop-ment by the transferor.2In particular,overseas assembly of relatively new and unstandardized products tends to be undertaken withinfirm boundaries,while innovators seem more willing to resort to licensing and subcontracting in stan-dardized goods with few product development requirements.The product cycle hypothesis has also at-tracted considerable attention among interna-tional trade theorists eager to explore the*Department of Economics,Harvard University,Lit-tauer230,Cambridge,MA02138,National Bureau of Eco-nomic Research,and Centre for Economic Policy Research (e-mail:pantras@).I am grateful to Daron Acemoglu,Marios Angeletos,Gene Grossman,and Jaume Ventura for invaluable guidance,and to Richard Baldwin, Lucia Breierova,Francesco Franco,Gordon Hanson,El-hanan Helpman,Simon Johnson,Giovanni Maggi,Marc Melitz,and Roberto Rigobon for their helpful commentsand suggestions.The paper was substantially improved by the thoughtful comments of the editor and two anonymous referees.I have also benefited from suggestions by seminar participants at various institutions.Thefirst draft of this paper was written while visiting the International Econom-ics Section at Princeton University,whose hospitality is gratefully acknowledged.I have also benefited fromfinan-cial support from the Bank of Spain.All remaining errors are my own.1See William Gruber et al.(1967),Seev Hirsch(1967), Louis T.Wells,Jr.(1969),and Thomas G.Parry(1975)for early tests of the theory.2See,for instance,Robert W.Wilson(1977),Edwin Mansfield et al.(1979),Mansfield and Anthony A.Romeo (1980),and William H.Davidson and Donald G.McFetridge(1984,1985).These studies will be discussed in more detail in Section III.1054macroeconomic and trade implications of Ver-non’s insights.Paul Krugman(1979)developed a simple model of trade in which new goods are produced in the industrialized North and ex-changed for old goods produced in the South. In order to concentrate on the effects of product cycles on tradeflows and relative wages,Krugman(1979)specified a very simple form of technological transfer,with new goods becoming old goods at an exogenous rate.This “imitation lag,”as he called it,was later endo-genized by Gene M.Grossman and Elhanan Helpman(1991a,b)using the machinery devel-oped by the endogenous growth literature.In particular,Grossman and Helpman(1991a,b) developed models in which purposeful innova-tion and imitation gave rise to endogenous prod-uct cycles,with the timing of production transfer being a function of the imitation effort exerted byfirms in the South.3As the empirical literature on the product cycle suggests,how-ever,the bulk of technology transfer is driven by voluntary decisions of Northernfirms,which choose to undertake offshore production within firm boundaries or transact with independent subcontractors or licensees.4In this paper,I provide a theory of the prod-uct cycle that is much more akin to Vernon’s (1966)original formulation and that delivers implications that are very much in line with the findings of the empirical literature discussed above.In the model,goods are produced com-bining a high-tech input,which I associate with product development,and a low-tech input, which is meant to capture the simple assembly or manufacturing of the good.As in Grossman and Helpman(1991a,b),the North is assumed to have a high enough comparative advantage in product development so as to ensure that this activity is always undertaken there.My speci-fication of technology differs,however,from that in Grossman and Helpman(1991a,b)in that I treat product development as a continu-ously active sector along the life cycle of a good.The concept of product development used here is therefore quite broad and is meant to include,among other things,the development of ideas for improving existing products,as well as the marketing and advertising of these prod-ucts.Following Vernon(1966),this specifica-tion of technology enables me to capture the standardization process of a good along its life cycle.More specifically,I assume that the con-tribution of product development to output(as measured by the output elasticity of the high-tech input)is inversely related to the age or maturity of the good.Intuitively,the initial phases of a product’s life cycle entail substantial testing and retesting of prototypes,as well as considerable marketing efforts to make con-sumers aware of the existence of the good.As the good matures and production techniques become standardized,the mere assembly of the product becomes a much more significant input in production.Following Vernon(1966)and contrary to Grossman and Helpman(1991a,b),I allow Northernfirms to split the production process internationally and transact with manufacturing plants in the South.5With no frictions to the international fragmentation of the production process,I show that the model fails to deliver a product cycle.Intuitively,provided that labor is paid a lower wage in the South than in the North,manufacturing will be shifted to the South even for the most unstandardized, product development–intensive goods.Vernon (1966)was well aware that his theory required some type of friction that delayed offshore assem-bly.In fact,he argued that in the initial phase of a product’s life cycle,overseas production would be discouraged by a low price elasticity3See Richard A.Jensen and Marie C.Thursby(1987), and Paul S.Segerstrom et al.(1990)for related theories of endogenous product cycles.See also Edwin i (1998)for an interesting extension of the Grossman andHelpman(1991a)model that incorporates foreign direct investment.4Grossman and Helpman(1991b)claimed that purpose-ful imitation was an important driving force in the transfer of production of microprocessors from the United States and Japan to Taiwan and Korea.Based on recent studies,I argue below that even in the case of the electronics industry, the spectacular increase in the market share of Korean producers might be better explained by technology transfer from foreign-basedfirms than by simple imitation by do-mesticfirms in Korea.5There is a recent literature in international trade docu-menting an increasing international disintegration of the production process(cf.,Robert C.Feenstra,1998;Kei-Mu Yi,2003).A variety of terms has been used to refer to this phenomenon:“international outsourcing,”“slicing of the value chain,”“vertical specialization,”“global production sharing,”and many others.Feenstra(1998)discusses the widely cited example of Nike,which subcontracts most parts of its production process to independent manufactur-ing plants in Asia.1055VOL.95NO.4ANTRA`S:INCOMPLETE CONTRACTS AND THE PRODUCT CYCLEof demand,the need for a thick market for inputs,and the need for swift and effective com-munication between producers and suppliers. This paper,instead,supports the view that what limits the international fragmentation of the production process is the incomplete nature of contracts governing international transac-tions.Building on the seminal work of Oliver E. Williamson(1985)and Sanford J.Grossman and Oliver D.Hart(1986),I show that the presence of incomplete contracts creates hold-up problems,which in turn give rise to suboptimal relationship-specific investments by the parties involved in an international transac-tion.The product development manager of a Northernfirm can alleviate this type of distor-tions by keeping the manufacturing process in the North,where contracts can be better en-forced.In choosing between domestic and over-seas manufacturing,the product development manager therefore faces a trade-off between the lower costs of Southern manufacturing and the higher incomplete-contracting distortions asso-ciated with it.This trade-off is shown to lead naturally to the emergence of product cycles: when the good is new and unstandardized, Southern production is very unattractive be-cause it bears the full cost of incomplete con-tracting(which affects both the manufacturing and the product development stages of produc-tion)with little benefit from the lower wage in the South.Conversely,when the good is mature and requires very little product development, the benefits from lower wages in the South fare much better against the distortions from incom-plete contracting,and if the Southern wage is low enough,the good is manufactured in the South.Following the property-rights approach to the theory of thefirm(Grossman and Hart,1986; Hart and John H.Moore,1990),the same force that creates product cycles in the model,i.e., incomplete contracts,opens the door to a par-allel analysis of the determinants of ownership structure,which I carry out in Section II.As in Grossman and Hart(1986),I associate owner-ship with the entitlement of some residual rights of control.When parties undertake noncontract-ible,relationship-specific investments,the allo-cation of these residual rights has a critical effect on each party’s ex post outside option, which in turn determines each party’s ex ante incentives to invest.Ex ante efficiency(i.e.,transaction-cost minimization)is shown to dic-tate that residual rights be controlled by the party whose investment contributes most to the value of the relationship.In terms of the model, the attractiveness of integrating the transfer of production to the South for a Northern product development manager is shown to be increasing in the output elasticity of product development, and thus decreasing in the maturity of the good at the time of the transfer.As a result,a new version of the product cycle emerges.If the maturity at which manu-facturing is shifted to the South is low enough, production will be transferred internally to a wholly owned foreign affiliate in the South,and the Northernfirm will become a multinational firm.In such case,only at a later stage in the product’s life cycle will the product develop-ment managerfind it optimal to give away the residual rights of control and assign assembly to an independent subcontractor in the South,an arrangement that is analogous to the Northern firm licensing its technology(high-tech input). For a higher maturity of the good at the time of the transfer,the model predicts that the transfer to the South will occur directly at arm’s length and multinationals will not arise.In Section III, I discuss several cross-sectional and time-series implications of the model and relate them to the empirical literature on the product cycle.For instance,the model is shown to be useful for understanding the evolution of the Korean elec-tronics industry after the Korean War.The paper is structured as follows.Section I develops a simple dynamic model that shows how the presence of incomplete contracts gives rise to product cycles.In Section II,I allow for intrafirm production transfers and describe the richer product life cycle that emerges from it. Section III reviews thefindings of the empirical literature on the product cycle and relates them to the predictions of the model.Section IV offers some concluding comments.I.Incomplete Contracts and the Life Cycle of aProductThis section develops a simple model in which a product development manager decides how to organize production of a particular good, taking the behavior of other producers and wages as given.I willfirst analyze the static1056THE AMERICAN ECONOMIC REVIEW SEPTEMBER2005problem and then show how a product cycle emerges in a simple dynamic extension in which the good gets standardized over time.A.SetupConsider a world with two countries,the North and the South,and a single good y pro-duced only with labor.I denote the wage rate in the North by w N and the wage rate in the South by w S.Consumer preferences are such that the unique producer of good y faces the following isoelastic demand function:(1)yϭ␭pϪ1/͑1Ϫ␣͒,0Ͻ␣Ͻ1 where p is the price of the good and␭is a parameter that the producer takes as given.6 Production of good y requires the develop-ment of a special and distinct high-tech input, x h,as well as the production of a special and distinct low-tech input,x l.As discussed in the introduction,the high-tech input is meant to comprise research and product development, marketing,and other similar skill-demanding tasks.The low-tech input is,instead,meant to capture the mere manufacturing or assembly of the good.Specialized inputs can be of good or bad quality.If either of the two inputs is of bad quality,the output of thefinal good is zero.If both inputs are of good quality,production of thefinal good requires no additional inputs and output is given by(2)yϭ␨z x h1Ϫz x l z,0ՅzՅ1 where␨zϭzϪz(1Ϫz)Ϫ(1Ϫz).The unit cost function for producing the high-tech input varies by country.In the North,pro-duction of one unit of a good-quality high-tech input requires the employment of one unit of Northern labor.The South is much less efficient at producing the high-tech input.For simplicity, the productivity advantage of the North is as-sumed large enough to ensure that x h is pro-duced only in the North.Meanwhile,production of one unit of good-quality low-tech input also requires labor,but the unit input requirement is assumed to be equal to1in both countries. Production of any type of bad-quality input can be undertaken at a positive but negligible cost. All types of inputs are assumed to be freely tradable.There are two types of producers:a research center and a manufacturing plant.A research center is defined as the producer of the high-tech input and will thus always locate in the North.I assume for now that the research center needs to contract with an independent manufac-turing plant for the provision of the low-tech input.In the next section,I will let the research center obtain the low-tech input from an inte-grated plant.As discussed at the beginning of this paper,I allow for an international fragmentation of the production process.Before any investment is made,a research center decides whether to pro-duce a high-tech input and,if so,whether to obtain the low-tech input from an independent manufacturing plant in the North or from one in the South.Upon entry,the manufacturer makes a lump-sum transfer T to the research center. Because,ex ante,there is a large number of identical,potential manufacturers of the good, competition among them will make T adjust so as to make the chosen manufacturer break even.7The research center chooses the location of manufacturing to maximize its ex ante prof-its,which include the transfer.Investments are assumed to be relationship specific.The research center tailors the high-tech input specifically to the manufacturing plant,while the low-tech input is customized according to the specific needs of the research center.In sum,the investments in labor needed to produce x h and x l are incurred upon entry and are useless outside the relationship.The setting is one of incomplete contracts in situations of international production sharing.In particular,it is assumed that only when both inputs are produced in the same country can an outside party distinguish between a good-quality and a6This demand function is derived from preferences in the general-equilibrium version of the model presented in the Appendix.7When y is produced by the manufacturing plant,the transfer T can be interpreted as a lump-sum licensing fee for the use of the high-tech input.The presence of this transfer simplifies the general-equilibrium model outlined in the Appendix.For the results in the present section,it would suffice to assume that nofirm is cash constrained,so that the equilibrium location of manufacturing maximizes the joint value of the relationship.1057VOL.95NO.4ANTRA`S:INCOMPLETE CONTRACTS AND THE PRODUCT CYCLEbad-quality intermediate input.8Hence,the man-ager of the research center and that of a Southern manufacturing plant cannot sign an enforceable contract specifying the purchase of a certain type of intermediate input for a certain price.If they did,the party receiving a positive payment would have an incentive to produce the bad-quality input at the negligible cost.It is equally assumed that no outside party can verify the amount of ex ante investments in labor.If these were verifiable,the managers could contract on them,and the cost-reducing benefit of producing a bad-quality input would disappear.For the same reason,it is as-sumed that the parties cannot write contracts con-tingent on the volume of sale revenues obtained when the final good is sold.The only contractible ex ante is the transfer T between the parties.9When the research center chooses to transact with a manufacturing plant in the North,the fact that labor investments are not contractible is irrelevant because the parties can always appeal to an outside party to enforce quality-contingent contracts.In contrast,when the low-tech input is produced by a plant in the South,no enforce-able contract will be signed ex ante and the two parties will bargain over the surplus of the re-lationship after the inputs have been produced.At this point,the quality of the inputs is observ-able to both parties and thus the costless bar-gaining will yield an ex post efficient outcome.I model this ex post bargaining as a Symmetric Nash Bargaining game in which the parties share equally the ex post gains from trade.10Because the inputs are tailored specifically to the other party in the transaction,if the two parties fail to agree on a division of the surplus,both are left with nothing.This completes the description of the model.The timing of events is summarized in Figure 1.B.Firm BehaviorAs discussed above,the North has a suffi-ciently high productivity advantage in produc-ing the high-tech input to ensure that x h is produced there.The decision of where to pro-duce the low-tech input,however,is nontrivial.In his choice,the manager of the research center compares the ex ante profits associated with two options,which I analyze in turn.(a)Manufacturing by an Independent Plant in the North.—Consider first the case of a re-search center that decides to deal with an inde-pendent manufacturing plant in the North.In that case,the two parties can write an ex ante quality-contingent contract that will not be re-negotiated ex post.The initial contract stipu-lates production of good-quality inputs in an amount that maximizes the research center’s ex ante profits,which from equations (1)and (2),and taking account of the transfer T ,are givenby ␲N ϭ␭1Ϫ␣␨z ␣x h ␣(1Ϫz )x l ␣zϪw N x h Ϫw N x l .It is straightforward to check that this program yields the following optimal price for the final good:8This can be interpreted as a physical constraint im-posed on the outside party,which might not be able to verify the quality of both inputs when these are produced in distant locations.More generally,the assumption is meant to cap-ture broader contractual difficulties in international transac-tions,such as ambiguous jurisdiction,language conflicts,or,more simply,weak protection of property rights in low-wage countries.9I take the fact that contracts are incomplete as given.Philippe Aghion et al.(1994),Georg No ¨ldeke and Klaus M.Schmidt (1995),and others have shown that allowing for specific performance contracts may lead to efficient ex ante relationship-specific investments.Nevertheless,Yeon-Koo Che and Donald B.Hausch (1999)have identified condi-tions under which specific performance contracts do not lead to first-best investment levels,and may actually have no value.10In Antra `s (2004),I extend the analysis to the case of Generalized NashBargaining.F IGURE 1.T IMINGOFE VENTS1058THE AMERICAN ECONOMIC REVIEW SEPTEMBER 2005p N͑z͒ϭw N ␣.Because the research center faces a constant elasticity of demand,the optimal price is equal to a constant markup over marginal cost.Ex ante profits for the research center are in turn equal to(3)␲N͑z͒ϭ͑1Ϫ␣͒␭ͩw N␣ͪϪ␣/͑1Ϫ␣͒.(b)Manufacturing by an Independent Plant in the South.—Consider next the problem faced by a research center that decides to transact with a plant in the South.As discussed above,in this case the initial contract stipulates only the trans-fer T.The game played by the manager of the research center and that of the manufacturing plant is solved by backward induction.If both producers make good-quality intermediate in-puts and thefirms agree in the bargaining,the potential revenues from the sale of thefinal good are Rϭ␭1Ϫ␣␨z␣x h␣(1Ϫz)x l␣z.In contrast,if the parties fail to agree in the bargaining,both are left with nothing.The quasi-rents of the relationship are therefore equal to sale revenues, i.e.,R.The Nash bargaining leaves each man-ager with one-half of these quasi-rents.Rolling back in time,the research center manager sets x h to maximize1⁄2RϪw N x h,while the manu-facturing plant simultaneously chooses x l to maximize1⁄2RϪw S x l.11Combining thefirst-order conditions of these two programs yields the following optimal price for thefinal good:p S͑z͒ϭ2͑w N͒1Ϫz͑w S͒z␣.If parties could write complete contracts in in-ternational transactions,the research center would instead set a price equal to (w N)1Ϫz(w S)z/␣.The overinflated price reflects the distortions arising from incomplete con-tracting.Intuitively,the parties will tend to un-derinvest in x h and x l because in the ex post bargaining they fail to capture the full marginal return to their investments.As a result,output will tend to be suboptimal and the move along the demand function will also be reflected in an inefficiently high price.Setting T so as to make the manufacturing plant break even leads to the following expres-sion for the research center’s ex ante profits: (4)␲S͑z͒ϭͩ1Ϫ1␣ͪ␭ͩ2(w N)1Ϫz(w S)z␣ͪϪ␣/͑1Ϫ␣͒.C.The Equilibrium ChoiceFrom comparison of equations(3)and(4),it follows that the low-tech input will be produced in the South only if A(z)Յ␻ϵw N/w S,where(5)A͑z͒ϵͩ1Ϫ␣͑1Ϫ12␣͒͑12͒␣/͑1Ϫ␣͒ͪ͑1Ϫ␣͒/␣z.It is straightforward to show that A(z)is nonin-creasing in z for zʦ[0,1],with lim z30A(z)ϭϩϱand A(1)Ͼ1.12This implies that(a)for high enough product development intensities of thefinal good,manufacturing is necessarily as-signed to a manufacturing plant in the North; and(b)unless the wage in the North is higher than that in the South,manufacturing by an independent plant in the South will never be chosen.Intuitively,the benefits of Southern as-sembly are able to offset the distortions created by incomplete contracting only when the man-ufacturing stage is sufficiently important in pro-duction or when the wage in the South is sufficiently lower than that in the North.To make matters interesting,I assume that:ASSUMPTION1:␻ϾA(1)Ͼ1.In Antra`s(2004),I show that this condition necessarily holds in a simple general-equilibrium extension of the model,in which the relative wage␻is endogenously pinned down.Intuitively,in the general equilibrium the relative wage in the North necessarily adjusts to11It is easily checked that in equilibrium both partiesreceive a strictly positive ex post payoff from producing a good-quality input.It follows that bad-quality inputs are never produced.12This follows from the fact that(1Ϫ␣x)x␣/(1Ϫ␣)is increasing in x for␣ʦ(0,1)and xʦ(0,1).1059VOL.95NO.4ANTRA`S:INCOMPLETE CONTRACTS AND THE PRODUCT CYCLEensure positive labor demand in the South.This extension is briefly outlined in the Appendix.A salient feature of the analysis is that as long as contracts governing international transactions are incomplete,the equilibrium wage in the North necessarily exceeds that in the South.13Assumption 1ensures that ␲N (z )Ͻ␲S (z )for sufficiently high z ʦ[0,1].Figure 2depicts the profit-maximizing choice of location as a func-tion of z .It is apparent that:LEMMA 1:Under Assumption 1,there exists a unique threshold z ៮ʦ(0,1)such that the low-tech input is produced in the North if z Ͻz ៮ϵA Ϫ1(␻),while it is produced in the South if z Ͼz ៮ϵA Ϫ1(␻),where A (z )is given by equation (5)and ␻is the relative wage in the North.From direct inspection of Figure 2,it is clear that an increase in the relative wage in the North reduces the threshold z ៮.Intuitively,an increase in ␻makes Southern manufacturing relatively more profitable and leads to a reduction in the measure of product development intensities for which the whole production process stays in the North.D.Dynamics:The Product Cycle As discussed earlier,one of the premises of Vernon’s (1966)original product cycle hypoth-esis is that as a good matures throughout its life cycle it becomes more and more standardized.14Vernon believed that the unstandardized nature of new goods was crucial to understanding that they would first be produced in a high-wage country.To capture this standardization process in a simple way,consider the following simple dy-namic extension of the static model developed above.Time is continuous,indexed by t ,with t ʦ[0,ϱ).Consumers are infinitely lived and,at any t ʦ[0,ϱ),their preferences for good y are captured by the demand function (1).The rela-tive wage ␻is assumed to be time-invariant.15The output elasticity of the low-tech input is instead assumed to increase through time.In particular,this elasticity is given byz ͑t ͒ϭh ͑t ͒,with h Ј͑t ͒Ͼ0,h ͑0͒ϭ0,and lim t 3ϱh ͑t ͒ϭ1.I,therefore,assume that the product develop-ment intensity of the good is inversely related to its maturity.Following the discussion at the beginning of this paper,this is meant to capture the idea that most goods require a lot of R&D and product development in the early stages of their life cycle,while the assembling or manu-facturing becomes a much more significant in-put in production as the good matures.I will take these dynamics as given,but it can be shown that,under Assumption 1,profits for the Northern research center are weakly increasing in z .It follows that the smooth process of stan-dardization specified here could,in principle,be derived endogenously in a richer framework that incorporated some costs of standardiza-13Another appealing characteristic of the general-equilibrium analysis is that the cross-sectional picture that emerges from the model is very similar to that in the classical Ricardian model with a continuum of goods of Rudiger Dornbusch et al.(1977).14In discussing previous empirical studies on the loca-tion of industry,Vernon wrote,“In the early stages of introduction of a new good,producers were usually con-fronted with a number of critical,albeit transitory,condi-tions.For one thing,the product itself may be quite unstandardized for a time;its inputs,its processing,and its final specifications may cover a wide range.Contrast the great variety of automobiles produced and marketed before 1910with the thoroughly standardized product of the 1930s,or the variegated radio designs of the 1920s with the uni-form models of the 1930s”(Vernon,1966,p.197).15The latter assumption is relaxed in the general equi-librium version of the model developed in Antra `s (2004)and sketched in theAppendix.F IGURE 2.T HE C HOICEOFL OCATION1060THE AMERICAN ECONOMIC REVIEW SEPTEMBER 2005。

Starting out & Understanding ideas词汇知识·自主学习Ⅰ. 根据语境及汉语提示写出正确的单词1. contrast dramatically对比显著2. their natural habitat它们的自然栖息地3. to multiply rapidly 快速繁殖4. the exploding rabbit population 突然增加的兔子数量5. a conservation project 一个保护项目6. decrease from 130, 000 to around 10, 000从130 000减少到大约10 0007. delay our departure延误我们的行程8. a small incident 一件小事9. the military intervention军事干预10. owe you our thanks 向你表示感谢11. the island’s ecology岛上的生态12. cause some land to collapse导致一些土地坍塌Ⅱ. 用适当的介词或副词填空1. The rats and mice quickly took over the island.2. We human beings should live in harmony with mother nature.3. The number of cats also increased, which in turn led to more cats hunting the birds.4. The end result was that parakeets, once large in number and native to the island, died out in 1891.5. Even after Macquarie Island became an official nature reserve in the 1970s, the rabbits remained out of control.6. What’s more, we can come up with our own ideas and learn more through discussion.7. The cats subsequently developed an appetite for the birds.8. The cats in consequence turned their attention—and their stomachs—back to the native birds.9. The rat, mouse and rabbit problem needed solving once and for all.10. It turned out that they developed an immunity to the virus.Ⅲ. 根据课文及汉语提示补全句子1. The green grass and bare rock of its landscape contrast dramatically, giving it a wild and natural beauty (使它具有一种野性和自然的美).2. Loose on the island, they did what rabbits do best(兔子们尽其所能)—they multiplied rapidly and began eating the native vegetation and digging holes, which caused soil erosion (造成水土流失).3. Experts felt it necessary to come up with a plan to(专家感觉有必要想出一个计划) remove all the rabbits from the island.4. But as the saying goes (常言道), “While the cat’s away, the mice will play. ”5. The next step is to remove the last remaining invading species, and that’s whereI come in(这就是我的切入点)—with my dogs.1. -tion 常用于动词后构成名词conserve—conservation 保护correct—correction改正invent—invention 发明congratulate—congratulation祝贺2. v. +up with 构成动词短语come up with 提出, 想出keep up with 跟上, 赶上put up with 容忍, 忍受end up with 以……结束阅读研析·合作学习Task 1 框架宏观建构: 整体理解Skim the passage and fill in the blanks.Part 1(Para. 1) A. The island’s more recent history is a tragic story. Part 2(Paras. 2～5) B. Macquarie Island enjoys a wild and natural beauty.Part 3(Para. 6) C. There are some measures to deal with the problem. Part 1: B Part 2: A Part 3: CTask 2 文本微观剖析: 细节探究1. Choose the best answer.(1)Which of the following is NOT true about Macquarie Island?A. It is in the South-west Atlanta Ocean.B. It lies halfway between Australia and Antarctica.C. It is a UNESCO World Heritage Site.D. It has a long, thin shape.(2)Who caused the tragedy happening on Macquarie Island?A The cats. B. The rabbits. C. The mice. D. Humans.(3)Rabbits caused many bad effects except that______.A. many holes were dugB. the number of cats increasedC. parakeets died out in 1891D. the number of mouse decreased(4)What can we infer from the fifth paragraph?A. The virus was effective and could solve all the problems.B. The departure of cats proves right.C. It is no easy task to remove invading species.D. The rats and mice caused more harm than the rabbits.(5)What can we learn from the last paragraph?A. Those trained dogs may cause other bad effects.B. The intervention is long but worthwhile.C. Poison can harm the native animals.D. The author is unsure about the result.答案: (1)～(5)ADDCB2. Long sentences analysis.译文: 由于在岛上松散养殖, 兔子们做了它们最擅长的事情——他们快速繁殖, 开始啃食当地植物, 并挖掘洞穴, 这导致了土地侵蚀。