今天有考试，没时间仔细看了，先转在这里吧
Last week at the department colloquium coffee hour, several
students engaged the faculty in a discussion about our Ph.D.
program. It became clear that many of the students did not
understand the basics; they were surprised at some of the questions
and confused by some of the answers.
These notes provide basic information about the purpose of a Ph.D.
program in an attempt to help students decide whether to pursue a
Ph.D. degree.
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The Basics
A Doctor of Philosophy degree, abbreviated Ph.D., is the highest
academic degree anyone can earn. Because earning a Ph.D. requires
extended study and intense intellectual effort, less than one
percent of the population attains the degree. Society shows respect
for a person who holds a Ph.D. by addressing them with the title
``Doctor''.
To earn a Ph.D., one must accomplish two things. First, one must
master a specific subject completely. Second, one must extend the
body of knowledge about that subject.
Mastering A Subject
To master a subject, a student searches the published literature to
find and read everything that has been written about the subject.
In scientific disciplines, a student begins by studying general
reference works such as text books. Eventually, the student must
also search scholarly journals, the publications that scientists
use to exchange information and record reports of their scientific
investigations.
Each university establishes general guidelines that a student must
follow to earn a Ph.D. degree, and each college or department
within a university sets specific standards by which it measures
mastery of a subject. Usually, in preparing for Ph.D. work in a
given field, a student must earn both a Bachelor's and Master's
degree (or their equivalent) in that field or in a closely related
field. To demonstrate complete mastery of the subject, a student
may be required to complete additional graduate-level courses,
maintain a high grade average, or take a battery of special
examinations. In many institutions, students must do all three.
Because examinations given as part of a Ph.D. curriculum assess
expert knowledge, they are created and evaluated by a committee of
experts, each of whom holds a Ph.D. degree.
Extending Knowledge
The essence of a Ph.D., the aspect that distinguishes Ph.D. study
from other academic work, can be summarized in a single word:
research. To extend knowledge, one must explore, investigate, and
contemplate. The scientific community uses the term research to
capture the idea.
In scientific disciplines, research often implies experimentation,
but research is more than mere experiments -- it means
interpretation and deep understanding. For Computer Scientists,
research means searching to uncover the principles that underlie
digital computation and communication. A researcher must discover
new techniques that aid in building or using computational
mechanisms. Researchers look for new abstractions, new approaches,
new algorithms, new principles, or new mechanisms.
To complete a Ph.D., each student must present results from their
research to the faculty in a lengthy, formal document called a
dissertation (more popularly referred to as a thesis). The student
must then submit their dissertation to the faculty and defend their
work an oral examination.
Relationship To Products
In some cases, the results of scientific research can be used to
develop new products or improve those that exist. However,
scientists do not use commercial success or potential commercial
profits as a measure of their work; they conduct investigations to
further human understanding and the body of knowledge humans have
compiled. Often, the commercial benefits of scientific research are
much greater in the long-term than in the short-term.
Research Activities
Computer Science research can include such diverse activities as
designing and building new computer systems, proving mathematical
theorems, writing computer software, measuring the performance of a
computer system, using analytical tools to assess a design, or
studying the errors programmers make as they build a large software
system. Because a researcher chooses the activities appropriate to
answer each question that arises in a research investigation, and
because new questions arise as an investigation proceeds, research
activities vary from project to project and over time in a single
project. A researcher must be prepared to use a variety of
approaches and tools.
A Few Questions To Ask
Many of you are trying to decide whether to pursue a Ph.D. degree.
Here are a few questions you might ask yourself.
1. Do you want a research career?
Before enrolling in a Ph.D. program, you should carefully consider
your long-term goals. Because earning a Ph.D. is training for
research, you should ask 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 people have managed to obtain a
research position without a Ph.D., but they are the exception, not
the rule). If, however, you want a non-research career, a Ph.D. is
definitely not for you.
2. Do you want an academic position?
A Ph.D. is the de facto ``union card'' for an academic position.
Although it is possible to obtain an academic position without a
Ph.D., the chances are low. Major universities (and most colleges)
require each member of their faculty to hold a Ph.D. and to engage
in research activities. Why? To insure that the faculty have
sufficient expertise to teach advanced courses and to force faculty
to remain current in their chosen field. The U.S. State Department
diplomatic protocol ranks the title ``professor'' higher than the
title ``doctor''. It does so in recognition of academic
requirements: most professors hold a Ph.D., but not all people who
hold a Ph.D. degree are professors.
3. Do you have what it takes?
It is difficult for an individual to assess their own capabilities.
The following guidelines and questions may be of help.
Intelligence:
In your college and graduate courses, were you closer to the top of
your class or the bottom? How well did you do on the GRE or other
standardized tests?
Time:
Are you prepared to tackle a project larger than any you have
undertaken before? You must commit to multiple years of hard work.
Are you willing to reduce or forego other activities?
Creativity:
Research discoveries often arise when one looks at old facts in a
new way. Do you shine when solving problems? Do you like ``brain
teasers'' and similar puzzles? Are you good at solving them? In
school, did you find advanced mathematics enjoyable or difficult?
Intense curiosity:
Have you always been compelled to understand the world around you
and to find out how things work? A natural curiosity makes research
easier. Did you fulfill minimum requirements or explore further on
your own?
Adaptability:
Most students are unprepared for Ph.D. study. They find it
unexpectedly different than course work. Suddenly thrust into a
world in which no one knows the answers, students sometimes
flounder. Can you adapt to new ways of thinking? Can you tolerate
searching for answers even when no one knows the precise questions?
Self-motivation:
By the time a student finishes an undergraduate education, they
have become accustomed to receiving grades for each course each
semester. In a Ph.D. program, work is not divided neatly into
separate courses, professors do not partition tasks into little
assignments, and the student does not receive a grade for each
small step. Are you self-motivated enough to keep working toward a
goal without day-to-day encouragement?
Competitiveness:
If you choose to enroll in a Ph.D. program, you will compete with
others at the top. More important, once you graduate, your peers
will include some of the brightest people in the world. You will be
measured and judged in comparison to them. Are you willing to
compete at the Ph.D. level?
Maturity:
Compared to coursework, which is carefully planned by a teacher,
Ph.D. study has less structure. You will have more freedom to set
your own goals, determine your daily schedule, and follow
interesting ideas. Are you prepared to accept the responsibility
that accompanies the additional freedoms? Your success or failure
in Ph.D. research depends on it.
A few warnings:
Students sometimes enroll in a Ph.D. program for the wrong reasons.
After a while, such students find that the requirements overwhelm
them. Before starting one should realize that a Ph.D. is not:
Prestigious in itself
Almost everyone who has obtained a Ph.D. is proud of their efforts
and the result. However, you should understand that once you
graduate, you will work among a group of scientists who each hold a
Ph.D. degree. (One faculty member used to chide arrogant graduate
students by saying, ``I don't see why you think it's such a great
accomplishment -- all my friends have a Ph.D!'').
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 few people assume a Ph.D. in one subject automatically makes
you an authority on others. It is especially true in the science
communicaty; respect must be earned.
A goal in itself
A Ph.D. degree prepares you for research. If all you want is a
diploma to hang on the wall, there are much easier ways to obtain
one. After you graduate, you will have occasion to compare your
record of accomplishment to those of other scientists. You will
realize that what counts is the research work accumulated after a
scientist finishes their formal education.
A job guarantee
When an economy slows, everyone can suffer. In fact, some companies
reduce research before they reduce production, making Ph.D.s
especially vulnerable. Furthermore, once a person earns a Ph.D.,
many companies will not hire that person for a non-research
position. As in most professions, continued employment depends on
continued performance.
A practical way to impress your family or friends
Your mother may be proud and excited when you enroll in a Ph.D.
program. 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 motivation for the effort required.
Something you can ``try'' to find out how smart you are
Sorry, but it just doesn't work that way. Unless you make a total
commitment, you will fail. You will need to work long hours, face
many disappointments, stretch your mental capabilities, and learn
to find order among 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 consider
it a test, you will eventually walk away.
The only research topic you will ever pursue
Many students make the mistake of viewing their Ph.D. topic as a
research area for life. They assume each researcher only works in
one area, always pursues the same topic within that area, and
always uses the same tools and approaches. Experienced researchers
know that new questions arise constantly, and that old questions
can become less interesting as time passes or new facts are
discovered. The best people change topics and areas. It keeps them
fresh and stimulates thinking. Plan to move on; prepare for change.
Easier than entering the work force
You will find that the path to successful completion of a Ph.D.
becomes much steeper after you begin. The faculty impose
constraints on your study, and do not permit unproductive students
to remain in the program.
Better than the alternatives
For many students, a Ph.D. can be a curse. They must choose between
being at the top among people who hold a Masters degree or being a
mediocre researcher. The faculty sometimes advise students that
they must choose between being ``captain of the B team'' or a
``benchwarmer'' on the A team. Everyone must decide what they want,
and which profession will stimulate them most. But students should
be realistic about their capabilities. If you really cannot
determine where you stand, ask faculty members.
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 salaries of Ph.D. and M.S. positions, the average time
required to obtain a Ph.D., the value of stock options, and current
return on investments. For a period of at least five years that we
know, the payoff was clearly negative. Suffice it to say that one
must choose research because one loves it; a Ph.D. is not the
optimum road to wealth.
The good news:
Despite all our warnings, we are proud that we earned Ph.D. degrees
and proud of our research accomplishments. If you have the
capability and interest, a research career can bring rewards
unequaled in any other profession. You will meet and work with some
of the brightest people on the planet. You will reach for ideas
beyond your grasp, and in so doing extend your intellectual
capabilities. You will solve problems that have not been solved
before. You will explore concepts that have not been explored. You
will uncover principles that change the way people use computers.
The joy of research:
A colleague summed up the way many researchers feel about their
profession. When asked why he spent so many hours in the lab, he
noted that the alternatives were to go home, where he would do the
same things that millions of others were doing, or to work in his
lab, where he could discover things that no other human had ever
discovered. The smile on his face told the story: for him, working
on research was sheer joy.
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