Tuesday, February 19, 2008

Open problems in movie stunt coordination

Via Fark, stuntman is attempting a 24-mile skydive.

But Steve, of East London, said: “It’s the last great challenge left on Earth. Obviously it will be dangerous. We’re playing with a lot of unknowns. But it’s my job to assess risk and I don’t believe the problems are insurmountable.”
Last great challenge on Earth? Looks like all of us scientists can quit our jobs soon! :-)

Saturday, February 16, 2008

TREC blog retrieval

Jonathan Elsas presented in the Social Media Reading Group yesterday. He presented to us the very successful approach the CMU team took for the Blog Retrieval task at TREC 2007. Details are in this paper (pdf)

He brought up the point that TREC has the cool property of being "task oriented", which is not always the case with data mining research (and is a criticism of the 'what do evolving graphs look like?' approach I tend to take with my own research).

Another point he made is that no teams at TREC (successfully) used two common properties of data that *are* important in the non-task-oriented research in social media: timestamps and link analysis. He did not seem to think that simply aren't "useful" properties, only that nobody figured out how to use them properly.

While I think that link analysis could be used, it certainly could not be used without some significant text analysis. My impression is that link analysis is useful for tasks like measuring influence or information diffusion, or trust and authority. Relevance seems to me to be a much more text-dependent property.

Furthermore, relevance is a subjective measure, just like influence and authority. In fact, the difficulty in a lot of data mining research is the difficulty of finding a good evaluation of your results. TREC scored the entries with human-tagging. If the goal was to find relative blog posts, then each team's algorithm would find some candidate posts, and the competitors themselves would then vote on which seemed best. And that's probably the best we could do for something so imprecise as "relevance".

It's really hard to do "science" when such complex beings as humans are involved in the measurements.

Jon also kindly lent me the WSDM proceedings, which I copied to my laptop and intend to review soon.

Tips on the Interview Process

Jeannette Wing, former CSD chair now at the NSF, came back to give her famous talk "Tips on the Job Interview Process". I was one of the "younger" grad students there-- since it had been three years since the last time she gave the talk there's the potential it wouldn't be given again in time for me to graduate. Also, sometimes the interview process for internships is similar.

Slides from the 2005 version of the talk.

Friday, February 15, 2008

Large-scale visualization reading group

Independent of the social media reading group (though I imagine some folks will participate in both), a visualization group has been founded by Peter Landwehr and Anita Sarma. And the first group meeting is on graph visualization (Thursday at 12:30 in the gradlounge). I'm stoked.

For the schedule and to subscribe to the mailing list, visit their wiki page.

Sunday, February 10, 2008

Boycotting assistant professorships

I'm currently reading A Ph.D. Is Not Enough: A Guide To Survival In Science. There is one chapter devoted to deciding on a career path, mainly between academia and industry/government.

It brings up some good arguments against going into academia. One oft-cited reason is the "begging for money"-- while you have the freedom to study whatever you like, you're limited by what you can find funding for. One thing that isn't often mentioned is that even fully-tenured professors still don't get to do whatever they like. By the time someone has tenure they're pretty well-known and have a lot of administrative stuff to take care of. Giving invited talks and schmoozing with NSF officials tends to crowd out time to spend meeting with students, never mind actually doing nitty-gritty research like they did in the golden days of grad school.

According to the chapter, junior professors generally have that minus the job security. Grants are often awarded based on track-record, which junior profs haven't had time to get. Also, in the first few years they need to start teaching courses from scratch rather than re-using things from past years. And, of course, they need to make a place for themselves in the community by reviewing papers, serving on PCs, writing papers, mentoring students, etc. Then, if they don't get tenure, they have to go away and start all over somewhere else.

Feibelman makes an argument that we simply shouldn't stand for that. By accepting an asst. prof job as-is, one consents to that mistreatment by The Man. And the intense competition that goes on for these few prized positions isn't giving The Man any incentive to change the way he does things. Feibelman suggests that one closely evaluate his or her priorities and recognize the inherent bias one who's spent so long in school may have toward academia (as in, we want to emulate our heroic advisors). He also suggests the option of making a name for oneself in industry/government labs and then walking right up to a university and getting a tenured or almost-tenured job right away.

I would tend to agree that a 6+ year hazing period, if that is indeed what it is, isn't good for the system. It appears from the outside that of the set of {JuniorProfessorship, Sleep, Family}, a mortal being can pick two at most. And whining about it won't do jack until enough sought-after PhDs start making ultimatums. However, I am not convinced that the ones fighting for professorships are going into it blindly. Anybody who's been in grad school for a few months knows the demands on their professors. People who have a choice between academia and industry and choose academia are usually willing to make sacrifices somewhere, whether it means their family or their hobbies or their health. Scientific research is the greater good. People who actually score academic jobs probably have done little else besides work for the last 10 years of their life-- if they didn't like it that way they would have changed some time ago. It works for them.

On the other hand, being focused to the point of peripheral blindness does somewhat correlate with being in grad school, so maybe some people are shooting for academia without knowing all the costs.

Friday, February 8, 2008

Slashdot moderation

In the social media reading group today, Yi-Chia Wang led discussion over Slash(dot) and Burn: Distributed Moderation in a Large Online Conversation Space, by Cliff Lampe and Paul Resnick at UMichigan. It's an interesting study of comment moderation on Slashdot.

I don't participate in comments on /., but I occasionally read them if I really don't have enough other things on the internet to distract me, and was always a little confused about how comments were moderated and decided upon (I never read this little FAQ of theirs). Users can vote for comments to be upgraded or downgraded. Most comments are not moderated (only 28% are), so there is a high tendency for default values between -1 and 2 to remain as-are: -1 is trolls, 0 for Anonymous Cowards, 1 for regular users, and 2 for users with good "karma", which is decided by whether you've posted.

One not-surprising thing was that at a median, 18 hours is how long it takes for 90% of a post's comments to happen. Not sure if it necessarily follows a power law dropoff, but if it does it is somewhat steeper than the -1.5 power law for post-responses in general for blogs that we wrote about in this paper, so I wonder if that is the case with comments for all blogs, or just high-traffic ones like Slashdot.

It's certainly an interesting moderating scheme, considering the computational methods for finding "interesting" things are not there yet.

Tuesday, February 5, 2008

Teaching Seminar

I just took my second grad student teaching seminar from the Eberly Teaching Center.
Unlike my education courses I took as an education major in undergrad, these seem to be useful. Today's was on Teaching Perspectives. There were five main perspectives presented:

Transmission: "Teacher pitches content to students."
Apprenticeship: "Teacher, who is knowledgeable about the content, can serve as a model / guide students"
Developmental: "Students learn by interacting with content."
Nurturing: "Encourage learning by forging relationship between student and teacher."
Social Reform: "Focus on ideals, everything else is bonus.

We took a Seventeen-magazine-style questionnaire that showed how we "scored" on each perspective with respect to our beliefs, actions, and intentions. I scored high on the first three, and low on the second two, while I would have expected myself to score lower on transmission and apprenticeship than I did.

However, I think the perspective depends on the class. I'm currently TAing for an undergrad/Master's level course in Machine Learning. While I think that social reform and emotional growth are important for young adults, I don't think that's my job. These students are paying a ton of tuition money, and here they're paying to be taught about machine learning. I'm much better equipped to give them their tuition's worth in cold, hard knowledge than in a great teacher-student relationship. They're perfectly capable of getting qualitative ideas from their philosophy courses and extracurriculars, and their nurturing from their friends and other relationships. However, if I were teaching, say, a course on statistical bullshit detection, I'd have a high priority on social reform, and if I were teaching a freshman class on literature or composition, I might want to incorporate more nurturing into the class.

Anyway, it's at least something to think about while I'm teaching. And I'll probably go to more of these seminars.