大家都知道保险丝

1908年提出了比较被保护元件两端电流的电流差动保护原理。1910年方向性电流保护开始应用。20年代初距离保护装置出现。

1927年出现了利用高压输电线上高频载波电流传送和比较输电线两端功率方向或电流相位的高频保护装置。

50年代，微波中继通讯开始应用于电力系统，出现了利用微波传送和比较输电线两端故障电气量的微波保护。并出现了利用故障点产生的行波实现快速继电保护的设想，并历经20年研究诞生了第一台型波保户户装置。

20世纪后期，大量的光纤通讯在电力系统中被采用，为新型继电保护奠定了基础！

20世纪末期，国外就提出了广域保护的理论，近几年国内一些保护方面的专业人士也在做这方面的研究！这是一种传统继电保护的转型，实现继电保护和自动控制两种功能，其考虑范围不再仅仅是一条输电线，一台变压器，一个机组，而是一个网内系统的安全稳定运行，因此对通信的要求也非常高，它所结合的工具有PMU、SCADA/EMS等等 以后我愿意和各位探讨这种新生事物Notes On The PhD Degree说说博士学位

Last week at the department colloquium coffee hour, several students ethe faculty in a discussion about our Ph.D. program. It became clear thaof the students did not understand the basics; they were surprised at sothe questions and confused by some of the answers.

上周系里咖啡时间的讨论会上，几个学生跟教员讨论了我们的博士课

程。显然，多数学生

对基本问题缺乏了解。他们对一些问题很惊讶而且对答案也弄不清楚。

These notes provide basic information about the purpose of a Ph.D. proan attempt to help students decide whether to pursue a Ph.D. degree.The Basics

对于博士学位课程的目的，这些解释提供了一些基本信息，可能有助于学生决定是否读博。

A Doctor of Philosophy degree, abbreviated Ph.D., is the highest academdegree anyone can earn. Because earning a Ph.D. requires extended stuintense intellectual effort, less than one percent of the population attainthe degree. Society shows respect for a person who holds a Ph.D. by adthem with the title ``Doctor''.

哲学博士，也就是PH.D，是一个人能取得的最高的学位。因为获得博士学位需要长期的

学习和强烈的心智努力。不到百分之一的人能成为博士。博士这一称呼表达了社会对博士学位持有者的尊敬。

To earn a Ph.D., one must accomplish two things. First, one must mastespecific subject completely. Second, one must extend the body of knowabout that subject.

要取得博士学位，必须做到两件事：一是完全掌握某一课题的知识，二是必须增加此课题的知识积累。

Mastering A Subject掌握一个课题

To master a subject, a student searches the published literature to find read everything that has been written about the subject. In scientificdisciplines, a student begins by studying general reference works such abooks. Eventually, the student must also search scholarly journals, thepublications that scientists use to exchange information and record repotheir scientific investigations.

要掌握一个课题，学生必须检索全部与本课题相关的公开发表的文献，并且阅读。

在科学学科中，学生首先从研究通用的参考材料比如课本开始。最后他必须研究学术期刊。

学术期刊就是科学家用来交换信息和纪录科学研究报告的地方。

Each university establishes general guidelines that a student must followearn a Ph.D. degree, and each college or department within a universityspecific standards by which it measures mastery of a subject. Usually, ipreparing for Ph.D. work in a given field, a student must earn both aBachelor's and Master's degree (or their equivalent) in that field or in aclosely related field. To demonstrate complete mastery of the subject, astudent may be required to complete additional graduate-level courses,

maintain a high grade average, or take a battery of special examinationmany institutions, students must do all three.

每个大学都有成为博士所需要执行的指导方针。而且每个学院或者系都有专门的标准，

来衡量对学科掌握的程度。通常在准备读给定领域的博士学位之前，学生必须先拿到

该领域（或者紧密相关的领域）的学士和硕士的学位（或者同等学历）。为了证明你

已经完全掌握了这个科目，学生可能需要完成附加的研究生水平（？）的科目课程，

或者有很高的等级分数（学分绩？），或者参加特别的考试选拔。很多机构要求全部这三个条件。

Because examinations given as part of a Ph.D. curriculum assess expertknowledge, they are created and evaluated by a committee of experts, whom holds a Ph.D. degree.

因为考试是博士课程的一部分，是要用来评判专家级的知识，所以由一个专家委员会来

命题和评判。专家们都必须有博士学位。Extending Knowledge 扩展知识

The essence of a Ph.D., the aspect that distinguishes Ph.D. study from oacademic work, can be summarized in a single word: research. To extenknowledge, one must explore, investigate, and contemplate. The scientcommunity uses the term research to capture the idea.

博士的本质，也是博士学习区别于其他学院工作的方面，简而言之就是一个字：研究。:)

为了扩展知识，你必须探索，调查，思考。科学共同体用这个术语——研究，来获得思想。

In scientific disciplines, research often implies experimentation, butresearch is more than mere experiments -- it means interpretation and deep

understanding. For Computer Scientists, research means searching to uthe principles that underlie digital computation and communication. Aresearcher must discover new techniques that aid in building or usingcomputational mechanisms. Researchers look for new abstractions, newapproaches, new algorithms, new principles, or new mechanisms. 在科学学科里里，研究常常意味着实验。但是研究不只是实验——它还包含解释和深刻

的理解。对于计算机科学家，研究意味着揭示数字计算和通讯之下的规律。一个

研究者必须发现新的技术来帮助建造或者使用计算设备。研究者寻找新的概念，

新的方法，新的算法，新的原理，或者新的装置。

To complete a Ph.D., each student must present results from their reseathe faculty in a lengthy, formal document called a dissertation (morepopularly referred to as a thesis). The student must then submit theirdissertation to the faculty and defend their work an oral examination. 要获得博士学位，学生必须通过冗长的、正式的文件即学位论文（通常也叫thesis）

来表述他的研究成果，提交给相关机构，并为论文做口头答辩。Relationship To Products 和产品的关系

In some cases, the results of scientific research can be used to develop products or improve those that exist. However, scientists do not usecommercial success or potential commercial profits as a measure of thethey conduct investigations to further human understanding and the boknowledge humans have compiled. Often, the commercial benefits of scresearch are much greater in the long-term than in the short-term.

有些情况下，科学研究的成果能被用于开发新产品或者提高现有产品。但是科学家不用

商业的成功或者潜在的商业利润来衡量他们的工作。他们把研究目的指

向更长远的人类

思维和人类已经整理的知识体系。经常的，科学研究的长期商业价值比短期的要大得多。Research Activities 研究活动

Computer Science research can include such diverse activities as designbuilding new computer systems, proving mathematical theorems, writinsoftware, measuring the performance of a computer system, using analtools to assess a design, or studying the errors programmers make as tbuild a large software system. Because a researcher chooses the activitappropriate to answer each question that arises in a research investigatand because new questions arise as an investigation proceeds, researchactivities vary from project to project and over time in a single project. researcher must be prepared to use a variety of approaches and tools. 计算机科学研究包括不同类型的活动，例如设计建造新计算机系统，提供算法，写计算

机软件，衡量计算机系统的性能，用分析工具评估设计，或者研究大型软件系统程序员

的错误。因为针对研究中出现的不同问题，研究者要选择相适应的操作，而且总会有新问题

产生，不同的课题和课题不同阶段研究活动是不一样的。研究者必须准备好用不同的方法和工具。

A Few Questions To Ask一些问题

Many of you are trying to decide whether to pursue a Ph.D. degree. Herfew questions you might ask yourself.

很多人将要决定是不是去读博士学位，这里有些问题你可能要问问自己先。

1. Do you want a research career? 你想干研究工作么？

Before enrolling in a Ph.D. program, you should carefully consider yourlong-term goals. Because earning a Ph.D. is training for research, you shouldask yourself whether a research position is your long-term goal. If it is, a

Ph.D. degree is the standard path to your chosen career (a few

managed to obtain a research position without a Ph.D., but they are theexception, not the rule). If, however, you want a non-research career, a Ph.D.is definitely not for you.

在参加博士课程之前，你应该仔细考虑你的长期目标。因为获得博士学位是一种研究的

训练。你要问问自己是否把研究工作作为自己的长期目标。如果是的，博士学位是你

走上研究工作的标准道路。（有些人不用博士学位也搞 研究，但他们是例外，不是常规）

如果不是，你想做非研究的工作，博士学位与你根本无关。2. Do you want an academic position? 2 你想获得学院职位么？

A Ph.D. is the de facto ``union card'' for an academic position. Althoughis possible to obtain an academic position without a Ph.D., the chances low. Major universities (and most colleges) require each member of thefaculty to hold a Ph.D. and to engage in research activities. Why? To insthat the faculty have sufficient expertise to teach advanced courses andforce faculty to remain current in their chosen field. The U.S. State

Department diplomatic protocol ranks the title ``professor'' higher thantitle ``doctor''. It does so in recognition of academic requirements: mosprofessors hold a Ph.D., but not all people who hold a Ph.D. degree areprofessors.

博士学位实际上是取得学眼职位的会员卡。虽然没有博士学位也能获得学院的职位，

但是机会比较小。主要的大学和多数学院要求每个教员都有博士学位从而能进行研究

工作。为什么呢？为了保证教员能有足够的专业能力教授高级课程，并且强迫教员在

自己的领域内跟得上形势。美国的传统惯例（？）认为教授比博士要高，这是学术的

要求：多数教授有博士学位，而不是所有的博士都能当教授。3. Do you have what it takes? 你具备条件了么

It is difficult for an individual to assess their own capabilities. The

following guidelines and questions may be of help.

自己评估自己的能力是困难的。下面几条方针和问题可能有所帮助。Intelligence:

In your college and graduate courses, were you closer to the top of yclass or the bottom? How well did you do on the GRE or other standarditests? 智力：

你的学院和研究上课程里，你是班里顶级水平还是垫底？GRE之类的标准考试考的如何？Time:

Are you prepared to tackle a project larger than any you have undertbefore? You must commit to multiple years of hard work. Are you willingreduce or forego other activities?时间：

你准备好要对付一个比你以往做过的任何课题都大的课题么？ 你必须苦干好几年。你

愿意为此减少或者牺牲其他活动么？Creativity:

Research discoveries often arise when one looks at old facts in a newDo you shine when solving problems? Do you like ``brain teasers'' and puzzles? Are you good at solving them? In school, did you find advancemathematics enjoyable or difficult?

创造性：研究发现常常来自用新的角度看待老的事实。你解决问题的时候机灵么？你

喜欢脑筋急转弯和类似的秘题么？你善于解决它们么？在学校，你觉得做数学难题是享受还是困难？

Intense curiosity:

Have you always been compelled to understand the world around youfind out how things work? A natural curiosity makes research easier. Difulfill minimum requirements or explore further on your own? 强烈的好奇心：

你经常强迫性的要了解身边的世界并且想发现其中的奥秘么？天生的好奇心使研究变得容易。

你是满足最小的需要还是进一步自己探索？Adaptability:

Most students are unprepared for Ph.D. study. They find it unexpectedifferent than course work. Suddenly thrust into a world in which no onthe answers, students sometimes flounder. Can you adapt to new waysthinking? Can you tolerate searching for answers even when no one knoprecise questions? 适应性：

多数学生没有准备好读博。他们发现读博和课程学习出乎意料的不同。突然进入一个

无人知道答案的世界，学生有时候会发慌。你能适应新的思考方式么？你能忍受寻找

一个根本没有人准确知道的答案么？Self-motivation:

By the time a student finishes an undergraduate education, they havbecome accustomed to receiving grades for each course each semester.Ph.D. program, work is not divided neatly into separate courses, profesnot partition tasks into little assignments, and the student does not recea grade for each small step. Are you self-motivated enough to keep working

toward a goal without day-to-day encouragement? 自我激励：

在学生完成本科教育之前，他们已经习惯于每学期每门课程得到分数。博士课程里，

工作不是清楚的分解到的课程的。教授不会把任务细分到很小，学生也不会每个小

的阶段都得到一个分数。你能够自觉的保持向一个目标努力工作，而不需要一天天的鼓励么？

Competitiveness:

If you choose to enroll in a Ph.D. program, you will compete with othat the top. More important, once you graduate, your peers will include sthe brightest people in the world. You will be measured and judged incomparison to them. Are you willing to compete at the Ph.D. level? 竞争：如果选择读博，你将和其他顶级人才竞争。更重要的是，你的同类将包括一些

世界上最聪明的人。你将被和他们相比来获得评价。你愿意在博士级别竞争么？Maturity:

Compared to coursework, which is carefully planned by a teacher, Phstudy has less structure. You will have more freedom to set your own gdetermine your daily schedule, and follow interesting ideas. Are you preto accept the responsibility that accompanies the additional freedoms? Ysuccess or failure in Ph.D. research depends on it.

成熟：相对于由老师仔细计划过的课程工作，博士学习的结构不怎么清晰。你有更多的自由

决定自己的目标和每天的日程。并且可以跟随有趣的思想。你准备好接收与这些自由相应的

责任了么？你的博士课程的成败都在此A few warnings: 警告：

Students sometimes enroll in a Ph.D. program for the wrong reasons. Awhile, such students find that the requirements overwhelm them. Beforstarting one should realize that a Ph.D. is not:

学生常常因为错误的理由决定读博。不久这些学生就会发现自己不能满足要求。开始之前，

你必须知道，博士学位不是：Prestigious in itself

Almost everyone who has obtained a Ph.D. is proud of their efforts aresult. However, you should understand that once you graduate, you wiamong a group of scientists who each hold a Ph.D. degree. (One facultyused to chide arrogant graduate students by saying, ``I don't see why think it's such a great accomplishment -- all my friends have a Ph.D!''). 自身就很有声望的：

每个博士都为自己的努力和成果而骄傲。但是你必须理解，你

一旦毕业，你将在一群人人都有博士学问的科学家中间工作。一个教员常常这样责骂

自大的毕业生：我看不出你有什么理由觉得自己有什么大本事——我的朋友都是博士！）

A guarantee of respect for all your opinions

Many students believe that once they earn a Ph.D. people will

automatically respect all their opinions. You will learn, however, that fewpeople assume a Ph.D. in one subject automatically makes you an authothers. It is especially true in the science communicaty; respect must bearned.

所有的意见都被尊敬的保证：

许多学生相信一旦当了博士，大家会自动尊敬自己的意见。但是你会明白，没人以为博士

学位会自动带给你在业内的权威地位。特别是在科学界，尊敬必须靠自己争取。

A goal in itself

A Ph.D. degree prepares you for research. If all you want is a diplomhang on the wall, there are much easier ways to obtain one. After yougraduate, you will have occasion to compare your record of accomplishmthose of other scientists. You will realize that what counts is the researcwork accumulated after a scientist finishes their formal education.本身就是目标：

博士学位是为你的研究做准备的。如果你的目标只是个墙上的文凭，这个很容易得到。毕业以后你就会有机会和其他的科学家比比成就。你会意识到，一个

科学家在完成了正规教育之后的研究积累才算数。A job guarantee

When an economy slows, everyone can suffer. In fact, some companresearch before they reduce production, making Ph.D.s especially vulneFurthermore, once a person earns a Ph.D., many companies will not hirperson for a non-research position. As in most professions, continuedemployment depends on continued performance. 工作的保证：

当经济发展变慢，每个人都会倒霉。实际上，一些公司首先削减研究，之后才是生产。

博士因此特别容易倒霉。更糟糕的，一旦你成了博士，很多公司就不会雇你做非研究的

工作了。多数行业里，持续的业绩才能带来持续的就业。A practical way to impress your family or friends

Your mother may be proud and excited when you enroll in a P

After all, she imagines that she will soon be able to brag about her child``the doctor.'' However, a desire to impress others is insufficient motivfor the effort required.

打动家人和朋友的实际途径：

拿了博士，你妈会很骄傲和激动。因为她起码认为她很快就可以拿她儿子吹牛“博士！”

但是吓人这样的动机，是不足以支撑读博所需付出的努力的。Something you can ``try'' to find out how smart you are

Sorry, but it just doesn't work that way. Unless you make a totalcommitment, you will fail. You will need to work long hours, face manydisappointments, stretch your mental capabilities, and learn to find ordeamong apparently chaotic facts. Unless you have adopted the long-range goal of

becoming a researcher, the day-to-day demands will wear you down. Standards

will seem unnecessary high; rigor will seem unwarranted. If you only coit a test, you will eventually walk away.有时候你可以试着看看自己有多聪明：

不好意思，但是不是这么回事。除非你作出彻底承诺，否则必定失败。你要长时间工作，

面对许多失望，延伸你的心智能力，学习从混乱的事实中找到秩序。除非你已经决定长

期目标为搞研究，否则日复一日的要求会把你磨倒。标准会显得没比要的高，严格程度

也会显得没道理。如果你只是把读博当成一种测试，你最后会走开的。The only research topic you will ever pursue

Many students make the mistake of viewing their Ph.D. topic as a resarea for life. They assume each researcher only works in one area, alwapursues the same topic within that area, and always uses the same toolapproaches. Experienced researchers know that new questions arise conand that old questions can become less interesting as time passes or neare discovered. The best people change topics and areas. It keeps themand stimulates thinking. Plan to move on; prepare for change.只追求一个研究课题：

许丢学生误以为博士课题就是一生的研究目标。他们以为研究者只在一

个领域里工作，

只研究领域里的同一个主题，用同一个工具和方法。有经验的研究者知道新的问题总是

持续出现，而旧问题会变得无趣，随着时间推移和新的事实被发现。最优秀的人会改变

主题和领域。这让他们鲜活而且能刺激思考。计划继续前进，准备改变。

Easier than entering the work force

You will find that the path to successful completion of a Ph.D. becommuch steeper after you begin. The faculty impose constraints on your sand do not permit unproductive students to remain in the program. 比加入就业大军容易：

一旦开始，你会发现成功完成博士学位的道路变得更艰难了。教员会约束你的学习，

并且不让干不出活来的学生继续呆在项目里。Better than the alternatives

For many students, a Ph.D. can be a curse. They must choose betweat the top among people who hold a Masters degree or being a mediocrresearcher. The faculty sometimes advise students that they must choobetween being ``captain of the B team'' or a ``benchwarmer'' on the AEveryone must decide what they want, and which profession will stimulmost. But students should be realistic about their capabilities. If you reacannot determine where you stand, ask faculty members. 比另一个选择好：

对于许多学生，博士学位是个魔咒。他们必须选择：成为硕士中的顶级人才，还是研究者

中的中等人。教员有时候建议学生，他们必须在B队的队长和A队的板凳队员之间选择。

每个人决定他想要的，和最能刺激他的。但是学生应该了解自己的能力。如果你不能自己判断，问问教员。

A way to make more money

While we haven't heard any statistics for the past couple of years,

graduate students used to estimate the ``payoff'' using the starting salof Ph.D. and M.S. positions, the average time required to obtain a Ph.Dvalue of stock options, and current return on investments. For a period

least five years that we know, the payoff was clearly negative. S

say that one must choose research because one loves it; a Ph.D. is not optimum road to wealth. 挣更多钱的方法路子：

当我们还不知道过去几年的统计数据，毕业生通常用博士和硕士的起步薪水，获得博士学

位所需的平均时间，股权价值，当前投资回报来评估盈利。据我们所知，至少五年内，

盈利显然是负的。可以说一个人选择研究，必须是基于热爱，博士不是发财的最佳途径。The good news: 好消息：

Despite all our warnings, we are proud that we earned Ph.D. degrees anof our research accomplishments. If you have the capability and interesresearch career can bring rewards unequaled in any other profession. Ymeet and work with some of the brightest people on the planet. You wilfor ideas beyond your grasp, and in so doing extend your intellectualcapabilities. You will solve problems that have not been solved before. Ywill explore concepts that have not been explored. You will uncover printhat change the way people use computers.

虽然有这些警告，我们还是为我们获得的博士学位和研究成果而骄傲。如果你有能力

和兴趣，一个研究职位能带来其他任何职业不能比的回报。你将遇到这个星球上最聪明的

人并且和他们合作。你将接触倒超过你所掌握的想法，极大的扩展你的智力水平。你将解

决从来没有被解决过的问题。你将探索从来没被探索过的概念。你会发现改变人们使用

计算机的方式的规律。The joy of research:

A colleague summed up the way many researchers feel about their profWhen asked why he spent so many hours in the lab, he noted that thealternatives were to go home, where he would do the same things that of others were doing, or to work in his lab, where he could discover thinthat no other human had ever discovered. The smile on his face told thefor him, working on research was sheer joy.

研究的乐趣：

一个同事总结了很多研究者对自己行业的感受。当被问及为什么他花这么多时间在实验室

里，他说他还有一个选择就是回家，但那是数百万其他人都在做的。而在实验室，他能发现

没有其他人发现过的东西。他脸上的微笑说明：对他来说，搞研究是纯粹的乐趣。-- 渡过高山和海洋 岁月就此流过在眼前

还记得我们偷偷摸摸学抽菸 那年我们十九岁 经过风霜和磨练 如今谁也无法再改变 还记得我们一起许下心愿 那年我们十九岁 随著时间的变迁 是否应该勇敢的面对

别再用一些安慰自己的谎言 再次欺骗你自己