Confessions of a researchaholic

April 12, 2016

Research coherence

Filed under: Real — liyiwei @ 7:31 pm
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One common advice on research is to have a coherent theme among our papers. I heard this from a bigwig around 2003 after getting my PhD.

This is one of these advices that I agree in principle but have violated in practice.

Yes, coherence can help recognition from the community, especially when one enters a new field.

However, I am not sure if this should be intentionally aimed for. Unless you are extremely smart and versatile, you are likely end up doing related stuff without even trying.

There is this implicit force that drags us towards similar, and thus incremental, ideas. We should fight against this force, not follow it.
So, just do whatever you like. You will have more fun and more likely to produce novel stuff which, even if lacks coherence, beats being incremental.

April 9, 2016

How to design talk slides

Filed under: Real — liyiwei @ 11:57 pm
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Using slides is a popular way to give presentations. I am not sure if it is the best way, but things can go very badly if done in the wrong way.

Take a look at Jim Blinn’s post about giving presentations.
Below are some quick high level suggestions. (I plan to refine this post later.)

Aim for simplicity and minimalism.

The slides are for conveying information to your audience, not serving as memo for the speaker.

Use intuitive pictures, illustrations, and animations, instead of texts and (worse) equations.

If you find yourself worrying about typography, it is a sign of too much texts.
No sentence should run over one line.

Rid of visual clutters like bullet points.

Gratuitous colors and unnecessary font variations tend to confuse people.

March 24, 2016

Recording and sharing presentation

Filed under: Real — liyiwei @ 9:43 am
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Talks are usually easier to understand than the corresponding papers. To get accepted, papers need to be written in a way that look formal and rigorous, but not necessarily easy to understand. However, when authors present their (accepted) papers, they tend to cut the chase and talk straight.

In the past, people have to attend conferences for the talks.
Nowadays, everyone can easily share their talk slides online.
Better yet, record and share your presentations as videos (e.g. via PowerPoint). This can be done during practices or official presentation.
You do practice your talks, right? So why not record during your rehearsals, so that you can review now and share later.
Recording in official presentation might be trickier, e.g. the conference may prefer presenters using a shared machine and the recording might disrupt your presentation, but can be worth a try.

I have not done this for my own talks, but realized it can be a good idea after watching a few recorded talks online. I really appreciate the efforts from the authors, and plan to do so for my future talks.

March 11, 2016

Why it is fun to review journal papers

Filed under: Real — liyiwei @ 1:15 pm
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After kindly agreeing to review a journal revision for the N-th time, the guy commented that “it’s the gift that keeps on giving!” 🙂

Conversation with collaborator X prior to a SIGGRAPH rebuttal

Filed under: Real — liyiwei @ 1:11 pm
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X: I’m really eager to see what the SIGGRAPH reviewers have in store for us this time… The suspense is killing me. =o

Li-Yi: I just assume they will screw me, and I am never disappointed. 🙂

X: Yes, that’s what I do as well, but I’m always amazed about how they always find ways to complain about the stuff you don’t expect. 😮

Li-Yi: If I can expect what others will think, I will be like some sort of x-men or superman. 🙂

February 1, 2016

The cat experiment

Filed under: Real — liyiwei @ 11:07 am
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Once, when I was around 9 or 10, I was visiting my aunt’s place.

One of the cousins, X, and I were standing near the swimming pool. The family cat walked by. Cousin X and I got into the discussion about whether cats can swim. I have seen a few dogs and at least one horse swam, so I was pretty sure the answer is yes (cats seem more agile). Cousin X disagreed (he is older but not necessarily smarter), so we decided to have a bet.

Clearly, the only way to settle the bet is to experiment, so I grabbed the cat and threw it into the pool.
(That was before the age of YouTube and Google, BTW.)

What followed was amazing, and happened like within a few milliseconds. The cat sprang on the water surface like a trampoline, and immediate landed back near my feet. It was dripping, so it clearly fell into the water, but I had no idea how it managed to jump back. Meanwhile, our debate remained unsettled.

I am trying to come up with a very concrete way to tell a new PhD student how to decide whether someone is suitable for (scientific) research. So here is my try. Let me know if you have better ideas.

Do you like to ask questions that seem interesting at least to you (e.g. whether cats can swim)?

Do you enjoy finding the answers yourself through investigations and experiments (e.g. grab the cat and throw it into the pool, and observe what happens)?

Are you very comfortable with the consequences, regardless of the outcomes of the experiments (e.g. the cat neither swam nor sank and my aunt beat me up)?

Can you do this continuously as a career? Imagine it is Friday lunch time, and all the works you have done this week have turned out to be failures (e.g. no other ways you have tried can tell you whether cats can swim).
You have no idea what is going to happen this afternoon when you try your 101th experiment with that cat.

If you hesitate for any of these questions or you think I am crazy, you are probably not suitable for research. At least, you will not be happy or successful.

Talent and personality are important; you have to be sufficiently smart and tough for research. But passion is even more important; the only way to be truly happy and productive is to do what you really like.

January 29, 2016

School versus job performance

Filed under: Real — liyiwei @ 4:29 pm
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How predictive is the school performance for the eventual job (and life) performance of an individual?

This is a very important question. The schools are supposed to educate what is actually useful. (But clearly that is not the case in practice.)

This is also a very broad question under perennial discussion.

In my personal experiences on the creative side of computer science (e.g. research and development for the cutting edge of graphics and HCI), there is a weak positive correlation between school and job performance (around 0.2 to 0.3 if I have to be numeric).
Good school performance reflects positive traits such as talent and work ethics, but also negative traits such as conformity, lack of creativity, and risk aversion.

This is why standard statistics, like grades, schools, and rankings, are not enough and sometimes even misleading. We have to look at more practical evidence, such as publications, projects, and recommendations.

This is also why recruiting top students and employees is very challenging. Top schools and companies do have advantages in attracting top talents, but we only get what we look for. Many of the best people I have worked so far had been bypassed by the traditional screening standards. Conversely, I have also seen many weak people in top institutions.

Maybe one day data analysis and machine learning will solve this problem.
Before that, I rely on the good old way of people reading.

Research opening

Filed under: Real — liyiwei @ 12:53 pm
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February 22 2016 update: I managed to spend all the expiring grant money already.

I have several opening research positions. Please contact me if interested, and help spread the information.

You pick whatever topic you like to do as long as (1) it can be published in a top graphics or HCI venue (e.g. SIGGRAPH, SIGGRAPH Asia, ToG, UIST, CHI), and (2) I have enough interests and expertise to help you.

Send me a brief description of your research plans along with the usual information, like your resume. Tell me why you want to work with me and how I can help you.

The first period will begin anytime from now and end on April 14 2016.
I can extend your contract if your performance is good enough.

These will be HKU positions, but other than school requirements you can work anywhere you like.

If you like to continue involve your current advisers or collaborators, just let me know. I usually like to know and collaborate with different people.

I have an expiring research grant that needs to be consumed prior to April 14 2016, and the remaining can be used only for hiring staff.

December 12, 2015


Filed under: Real — liyiwei @ 8:28 pm

During my PhD study, I observed how my adviser continued to code and experiment for his own projects, even after being very well established – tenured Stanford professor, computer graphics achievement award, etc.

After graduation I spent a decade in the industry as an engineer and researcher. For companies I worked for (NVIDIA and Microsoft), not coding feels worse than not talking (unless you are a manager).
Even when I consult (e.g. Lytro), I still opt to implement, even if the code cannot be shared due to IP reasons.

Thus, implementation has become an integral part of my workflow.
I found it the best way to (really) learn new topics, and more importantly a highly enjoyable process; I lose some mental balance without coding for more than a few days.

Maybe I am not smart enough, but I never understand why some CS people can get by without implementation.

For my past projects I either code with experienced collaborators, or leave it to the students for topics that I am already familiar with.
I have never code with a junior student in the same project, but I am starting that for a black-magic-like project.
I think this could be fun and mutually beneficial, and will report the experience later.

December 9, 2015

The PhD grind

Filed under: Real — liyiwei @ 6:10 pm
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I bumped into this PhD student memoir by Philip Guo, and liked it so much that I read the entire book within a few hours.

I highly recommend it to anyone doing research, especially junior PhD students.

There are many advices out there about research and PhD, but this memoir format provides concrete events that are easier to relate on a personal level.
It also helped that the fields covered are HCI and software engineering, which every CS major can understand to some degree.

In retrospect, I hope to have written something similar around the time of my PhD study. Back then I simply had too much fun for this, and I probably have too much selective bias now to write a genuine one.
But if you can write one, I would love to read.

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