Confessions of a researchaholic

November 12, 2016

Basis cases

Filed under: Real — liyiwei @ 8:38 pm
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Back in the good old days when I was working as a GPU architect in NVIDIA, we had suites of tests for various stages of GPU development: architecture, RTL, driver, real chips, etc.

Ogtest, consisting of tests written in OpenGL, can be applied to all stages. Each test is written to be as compact as possible, the tests are ordered from simple to complex, and collectively they cover the entire target space (e.g. all applications to run on the target GPU).

For example, the first test is to draw a flat colored triangle, the next is a textured triangle, and the next is called son-of-the-textured-triangle (with two textures instead of just one, if I remember correctly).
I then went on to add a test called daughter-of-the-textured-triangle (I am all in for gender equality) which consists of two textures but exercised a different path through the texturing and shading units (if I remember correctly).

I like to think of these as the basis test cases for the entire target space, analogous to basis vectors in linear algebra.

This applies to all research and development projects. Instead of jumping to debug full-scale applications, it can help to design a set of basis cases first. The process can clarify our thinking, and help us debug and explore algorithm/implementation issues. The basis cases can even be part of the analysis section of a research paper.

October 21, 2016

Research riddle

Filed under: Real — liyiwei @ 6:45 pm
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Identify the common relationships between the following pairs of papers.
🙂

Discrete element textures, SIGGRAPH 2011
Vignette: interactive texture design and manipulation with freeform gestures for pen-and-ink illustration, CHI 2012

Dynamic element textures, SIGGRAPH 2013
Draco: bringing life to illustrations with kinetic textures, CHI 2014

Motion field texture synthesis, SIGGRAPH Asia 2009
Energy Brushes: interactive tools for illustrating stylized elemental dynamics, UIST 2016

September 13, 2016

Paper acceptance rate

Filed under: Real — liyiwei @ 6:58 pm
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Since HKU asked for this and resumes do not usually contain failures, I reckon it could be a good idea to share my paper acceptance rate.

For SIGGRAPH (the top venue for computer graphics and interactive techniques, in case you don’t know), my life-time acceptance rate is 36%, and 40% in the last 5 years.

As a milestone of seniority, I couldn’t recall how many SIGGRAPH papers I have until doing this calculation.
🙂

I am not keeping track of my submissions to other venues (such as CHI, UIST, I3D, TVCG, EGSR, etc.), but I am pretty sure the overall rate is at least 50%, and much higher for some venues, such as EGSR (100%).

For reference, the overall acceptance rates of many graphics venues can be found under http://kesen.realtimerendering.com/.

August 18, 2016

Milestone of seniority

Filed under: Real — liyiwei @ 1:09 pm
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April 30, 2016

Strength in numbers

Filed under: Real — liyiwei @ 12:12 pm
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In his PhD application, a student indicated that he is collaborating with a famous professor on a recent SIGGRAPH project.

I asked that professor about the student. He told me that the project has 20 students (most are not co-authors), and the particular student is probably not even a secondary helper.

In comparison, most of my projects so far involve 0 or 1 student, and none over 2 students.
🙂

April 20, 2016

User interface

Filed under: Real — liyiwei @ 8:45 pm
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When I was in grad school I thought UI is about tuning widgets and doing user studies (a lot of research did exactly that). I preferred working on algorithms because they seem more interesting and more fundamental.

Later on, I realized how wrong I was. User interface is crucial as long as humans remain biological and machines remain mechanical.
A good UI can save a not so good algorithm, but not vice versa.
And UI research can also be fun and fundamental.

April 17, 2016

Hiring mistakes

Filed under: Real — liyiwei @ 6:43 pm
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Hiring PhD students is even harder than hiring employees because younger folks have more potential to grow.
And unlike an industry researcher who can let interns come and go, a university professor sticks with the students.

Two prior PhD applicants to HKU whom I passed on have turned out with outstanding performance.

One of them is still collaborating with me, so I did not regret as much. Actually, if he had not gone to another school we would not have access to some crucial hardware environment for our project, and his adviser might not have warmed back to SIGGRAPH. So I probably still made the right call.
🙂

I clearly have a lot to learn, and will have hundreds of cases to practice every year.

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.
=D

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
Tags: ,

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.

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