Confessions of a researchaholic

2013-04-10

Taking courses versus doing research

Filed under: Real — liyiwei @ 7:25 pm
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Students take courses in college, and do research in graduate school.

Taking courses and doing research share some common intellectual underpinnings. On the other hand, they are also very different. Different enough to make some college superstars completely fail in graduate schools.

When you take a course, everything is pre-designed and deterministic. You follow the instructions. And if you are smart and hardworking enough, you get good grades.

When you conduct a research project, very little is known a priori. The process is ambiguous and stochastic; your assumption may be wrong, your experiments may fail, sometimes you might not know what you are doing, and in the end your papers may get rejected. Being smart and hardworking can help. But if you have to follow clear instructions and you expect deterministic outcomes, you probably will not enjoy or be very good at research.

This is probably why, in my personal experience, the best research students might not have the best GPA, but they are usually creative, motivated, tough, and (most importantly) can get things done no matter what happens.
(Perfect GPA can be a reflection of conforming personality, which is not suitable for research. On the other hand, bad GPA is usually a reflection of intellectual or personality problems.)

The transition from undergrad to grad school is not always easy for everyone. My suggestion is to adopt the research mentality as early as possible. In particular, do not waste your time on courses; all you need is to pass the minimal requirements. If you have to, take courses that are research or project oriented. And start your research as early as possible, so that you will have more time to learn and adjust, and to accommodate all the potential failures and setbacks.

2013-03-31

How I bring up students

Filed under: Real — liyiwei @ 11:50 pm
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What

Stage 1: I will train your basic skills through a series of pet projects (e.g. building a mini software system or reproducing a paper). You are supposed to complete all these entirely on your own.

Stage 2: I will then directly take you to a real project aiming for the best venue of your field. I will work very closely with you on everything.

Why

I only have time for the best projects with the best students. The above 2-stage process is designed as a consequence.

I understand this is not an ordinary methodology. But experiences indicate that it is very effective in helping all students. In particular, the good ones can learn and publish as quickly as possible, while the not-so-good ones can realize as early as possible that they should explore other career options.

I disagree with the usual process of gradual bring-up by submitting to lower tier venues. This can spoil your mentality and motivation, as you will not work as hard as you should and grow as fast as you could. And even if you need non-top publications, it is faster to have those as failed attempts for top venues than direct submissions to lower venues.

For those of you who are not my internal or primary students, your primary adviser should have the final say about your study plan. Just come to me when you are ready for stage-2.

2013-03-26

About resubmission

Filed under: Real — liyiwei @ 7:21 pm
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Unfortunately, your paper was rejected by your favorite venue.
Now what? The decision for the next step depends on review opinions and your preferences.

It is not hard science: reviews are stochastic and humans are irrational.
(See earlier posts about rejections, and how to deal with them.)

So, the first thing is to figure out how much you should trust the reviews and your gut feelings.
Sometimes the reviews are right; maybe your paper is really not suitable for that venue (e.g. off topic, not enough contribution) and it is better to choose another venue.
But sometimes they are not; I have at least one submission that was summarized as “not having enough contribution” and I just went ahead with resubmission and the paper got in.

It also depends on whether you will enjoy continuing the work, and whether you think you can make significant improvements. If both conditions hold, it is probably a good idea to ignore the reviews.

Finally, consider opportunity cost. Given the same amount of time and efforts, you can either (1) resubmit the paper to your most favorite venue or (2) submit it to a lower tier and start a new work. Which one (you think) will make you happier and more productive?

PS: see my collaboration policy.

2013-03-25

Inertia

Filed under: Real — liyiwei @ 7:18 pm
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People tend to work on things which they have prior experiences with.

This is good for coherence; few have the talents to jump between completely unrelated things. But it can also be bad for creativity; we tend to lose the prospective after sticking around something for too long. Achieving the right balance is not easy, at least for me.

But it can become a bit easier with the presence of stern warning signs. It is time for me to move on, before it kills me.

Self: time to code the next new thing. Do not slack off. People are watching.

2013-03-15

Burnout

Filed under: Real — liyiwei @ 4:22 pm
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A recent PhD graduate whom I know well, who has been doing quite well in graphics research, just took a non-research job in a non-graphics position, among several postdoc offers from top research institutions.

The reasons he cited are numerous, but the 2 main ones are:

. He likes graphics research, but he is getting bored and tired of the SIGGRAPH game, including deadline crunch and dealing with reviewers.

. He would like to learn something new and try a different life style.

In a nutshell, I think he is burned out. I hope I have done my best to help him achieve work-life balance (I did that quite well myself, even when I was a grad student), but I guess it is just too hard for normal people to be much disciplined.

Then I realized that I probably also had some kind of burnout around my graduation. I took a non-research position as the first job, even though it was in a graphics company (NVIDIA). I also wanted to try learning new things (hardware architecture) and living a different style (engineer).

So I guess it is probably OK. People are not meant to be doing the same thing all the time. This is also why I like to try different job sectors and geographical locations.

There are two things to watch out, though, all based on my personal experiences: passion, and rust.

Passion

I have a very simple rule to choose jobs: do what you really like, and be very good at it.

Sometimes, when people get burned out, they might temporarily settle for something that they neither really like nor really be good at. But eventually, you will know if the job is not for you. I did not realize how much I like doing research until after I was not been able to spend enough time on it for about 3.5 years after my graduation.

The important thing is to get out there as quickly as possible. Otherwise, you will eventually become one of these people who are not really happy or good at their jobs but also cannot quit.

Rust

People tend to get rusty for skills that they have not practiced for a while. This is particularly so for advanced skills, like research.

So, make sure you do whatever you can to be active in research during your non-research job. Otherwise, you might not be able to come back, even if you want.

I have been trying my best to be engaged in research during my NVIDIA days. I even managed to publish a single authored graphics hardware paper. But it still took me about 2 to 3 years to get back in shape for SIGGRAPH after joining MSR. The difference between SIGGRAPH and other graphics venue is like the difference between playing professional sports and working out in a gym.
I guess SIGGRAPH is probably an extreme case, but I hope you get what I mean.

2013-02-14

Open mentoring

Filed under: Real — liyiwei @ 12:23 pm
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If you want to strengthen your credentials for school/job applications while having fun learning about computer science research without any additional costs or hassles, I can help you.

See below (and my advising style) for details, and let me know if you have questions or comments.
Please also help spread the news; we are making this world a better place.

Why

It is becoming more and more competitive to get to a good job or school. You need a glistering resume. And passive measures like grades, ranks, and standard test scores are no longer sufficient because they do not reflect the active skills which are crucial for today’s highly dynamic and creative job functions.

School application example: 20 years ago if you are a top 5 percent student from a number 1 department/school in your specific country/region with good GRE/TOEFL scores (all passive measures), you can probably get into MIT/Berkeley/Stanford PhD program without much problem.
Today, you will likely not make the cut without impressive active measures such as publications and recommendations from top people in your field.

Job application example: 20 years ago a Stanford PhD without any publication can probably beat a Tsinghua PhD with strong publications in getting a high tech job in the US. Today will be the exact opposite.

In a nutshell, active measures are gaining importance over passive measures. But they are also harder to come by entirely on your own.
This is why people are doing all these internships and school projects. The question is: how good are your internship/project mentors, and how much credibility their recommendations carry? If you plan to spend time on these, better pick a good mentor.

What

I have been mentoring and collaborating with many students and junior researchers for a while. I have this unique asynchronous style that is not only very effective (judging by the publication records and responses from my collaborators) but also very scalable (absolutely no resource constraint except our passion and commitment).

If you do well, you will get strong publications and strong letters of recommendation from me. I am well connected to top schools, companies, and recruiters. You will also have a lot of fun with your projects.
If you do not do well, you have nothing to lose, as long as you do not list me as a reference.

How

I work with you asynchronously through svn paper drafts and Google sites. It is up to you to decide when and where you work. The amount of time I spend on you is entirely proportional to your productivity. I seem to have this uncanny ability to remotely read human minds (and sense human emotions) more effectively than ordinary people can face-to-face (the origin of my “Jedi” nickname).

You start by telling me what interests you, and I brainstorm with you to find a good project direction.

I then pick a warm-up project, usually reproducing a known piece of work in your field of interest, such as writing a ray tracer (my favorite pet project for rendering) or implementing your favorite conference/journal paper.

Not everyone will survive this warm-up stage. But if you do, we move on to a creative project, aimed for a real conference or journal publication. You will have a chance to learn everything that ever needs to be learned about doing research and publishing a paper. I can claim this because I have several single-authored papers to prove the completeness of my skill-set. I also have papers with different numbers of authors to prove my collaboration and advising skills.

Who

I am most experienced with senior-undergrad + graduate students as well as junior lab researchers, but I do not have any hard constraints. It really depends on how we feel about each other.

I particularly like to help those who lack proper guidance; there appears to be many irresponsible/incompetent mentors out there, so I consider myself doing a useful social service.

If you want to become my internal student, you will need to go through this process anyway.

When

As indicated above, we can start anytime you like.

However, you might want to time your school/job applications. For example, it is not sensible to start working with me a month before your school/job application deadline, because I will have little to say about you. A good rule of thumb is to contact me at least a year ahead.

Where

As indicated above, you can work anywhere you like.
I have a shared online work-space for you to meet others, as well as channels for individual discussions.

I might be able to arrange a few internship quotas, but those are already very competitive, and frankly they make little (if any) difference for my mentoring style.

2013-01-25

Teaching

Filed under: Real — liyiwei @ 7:23 pm
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My attitude towards teaching could be reflected by how I would really like to write my teaching statement (for faculty job applications).
There will be only one sentence: “smart enough students can pick up everything themselves”.
(Note1: I know this is entirely doable because I pulled this off since I was 10 years old, and I did not consider myself to be very smart.)
(Note2: Of course this is not how I really wrote my teaching statement.)

With this backdrop, it should not be a surprise that I have never blogged a single entry about teaching, at least not mine. I do not even have teaching as a tag word.

I have considered teaching as a chore rather than enjoyment (unlike research), and my basic stance has not changed too much. (One main reason why I think it is better to start a research career as an industry lab scientist rather than a university professor.) But not until I really taught full-semester classes, especially large ones, did I start to appreciate teaching can be a fun thing to do, for two main reasons.

First, it can actually inspire my research ideas.

Second, and probably more important, teaching provides a great chance for massive mind reading and human studying, with moral justification for effective teaching. It is even more fun and challenging than reading individuals, one of my most favorite pastimes.

More posts to follow.

2013-01-07

Sharing code and data

Filed under: Real — liyiwei @ 1:08 am
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It is usually a very good idea to share the code and data along with our published papers. This will make it easier for others to test, understand, reproduce, and compare against our methods, which in turn can make us more popular, our papers more widely cited, and our technology more likely to be adopted by the industry and turned into real products.
Code and data repositories are also an important part of evaluating job applications.

(I have open sourced most of my first/single-authored projects, except my first 2 SIGGRAPH papers for which I could no longer find the code in the school server, which I greatly regret.)

Ideally the code should be in high quality, but even if not, sharing it can let others have a chance to improve the code (and motivate us to write good code).
It is fair to say that the code and data are no less important than the paper.

Some things to watch out for include institutional and legal constraints, such as trade secrets, copyrights, and patents, and not yet published future ideas.
These can be planned and managed via different git branches (e.g., a public branch that is gradually merged from a private branch).

2012-12-31

How to design demos

Filed under: Real — liyiwei @ 9:51 pm
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In a nutshell, a demo should properly demonstrate technical aspects with sufficient artistic appeals.

The technical part is usually more important, and can suffice alone for many science and engineering disciplines. However, the artistic part is also very important for graphics and HCI, or any fields which involve direct human perception and consumption.

Demos usually take a lot of time and efforts, on top of the usual workload in ideation, writing, algorithm, implementation, and experimentation. And whether you like it or not, a solid and novel algorithm cannot be adequately assessed or appreciated by the readers if it is not demonstrated through proper demos.

Thus, designing demos is kind of an art. Below are recent suggestions from Sylvain Lefebvre which I have found to be excellent.


A guideline that worked fine for me is to consider whether 1) the result demonstrates the technique properly and 2) the result looks just good enough that it appears useful; in particular we want to avoid people think that the example is contrived to only show the advantage of our approach.

The problem is that 1) and 2) sometimes compete with each other (e.g. a fantastic rendering possibly making it hard to properly see the motion, etc.). Also we do not want to spend too much time on 2), only enough that people will think that it is convincing.

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