30 October 2009

Link of the day: "Quitting the Paint Factory" by Mark Slouka

I enjoyed the essay "Quitting the Paint Factory" by Mark Slouka. Apparently, it was originally published in Harper's Magazine in 2004. Thanks to Gina Trapani for pointing it out in her original post. I think the main essence of the essay is captured by this quote (and Trapani agrees with me, I think):
Idleness is not just a psychological necessity, requisite to the construction of a complete human being; it constitutes as well a kind of political space, a space as necessary to the workings of an actual democracy as, say, a free press. How does it do this? By allowing us time to figure out who we are, and what we believe; by allowing us time to consider what is unjust, and what we might do about it. By giving the inner life (in whose precincts we are most ourselves) its due. Which is precisely what makes idleness dangerous. All manner of things can grow out of that fallow soil. Not for nothing did our mothers grow suspicious when we had "too much time on our hands." They knew we might be up to something. And not for nothing did we whisper to each other, when we were up to something, "Quick, look busy."

28 October 2009

Dave Pritchard on physics education

I've always found the topic of teaching and learning fascinating. Yesterday, I went to a talk by Professor David Pritchard of MIT. He helped develop the Mastering Physics software that is used in many American universities today. Back in the early 2000s, it wasn't called Mastering Physics, rather it was Cyber Tutor and piloted in the MIT freshman physics classes. I took notes during Prof. Pritchard's talk.
  • Students spend the most time and learn most from homework (education experts and parents agree on this point!). However, homework is the bottom priority for most professors.
  • Cyber Tutor acts like an expert physics tutor. Prof. Pritchard showed statistical data that proves the software is as effective as a real-person tutor. If a student is completely lost on a problem, he or she can ask for a hint. If a student answers incorrectly, the software can provide feedback such as "check your units."
  • A goal of software like Cyber Tutor is to teach students multiple representations of information and multiple approaches to solving problems. Experts know all of this, but they usually don't communicate this knowledge. Rather, they focus on the one fastest way to the answer.
  • Cyber Tutor can track learning trajectories. Each action can be logged: FA = first attempt, SA = second attempt, NF = no feedback to wrong answer, F = feedback to specific error, H = hint, S = subtasks, FS = failed subtasks. An example trajectory would be H → FA → F → SA.
  • The software is a treasure trove for data mining. In addition to assessing a student's skill, data can also be used to fix badly written problems.
  • Prof. Pritchard posted his "cheaters never prosper" plot. I didn't understand any of the statistics terminology, but the graph proved that students who copy the most do the worst on the exams. The cheaters are detected with the following criteria -- 1) Response is under one minute, 2) Response is correct.
  • Interestingly, copying had very little effect on conceptual learning. This is probably due to the fact that class attendance was required and the majority of class time was spent on conceptual learning. Of course, copying had a huge negative effect on analytical learning.
  • In another example of how detailed data mining can get, Prof. Pritchard showed a plot of percentage of homework completed vs time before homework's due date. As one would expect, the copiers did very little work until close to the deadline.
  • Men cheated more than women, and business majors cheated more than other majors. I didn't get the exact statistics unfortunately.
  • Conclusion: It is clear that copying has a large negative effect on learning outcomes. Therefore, professors should discourage copying. This has in fact happened at MIT, partly through eliminating second semester pass/no record grading.
  • The last part of the talk was called "what should we teach?" Unfortunately, I had to leave and go to another talk, so I didn't find out the answer.

26 October 2009

Why the New York subway has no recycling bins

I was wondering why the New York subway had no recycling bins, so I wrote to the MTA and asked. This was their response.
Response (Melissa Glasgow) - 10/26/2009 01:34 PM
This is in response to your recent e-mail to MTA New York City Transit suggesting recycling bins in the subway system.

We appreciate your interest in improving mass transit. You may be interested to know that all subway refuse is recycled on a post-collection basis. This method of post-collection recycling achieves the aim of totally recycled refuse from the subway system at a moderate cost, and eliminates the need for recycling receptacles in stations. Nevertheless, your suggestion has been referred to supervision in our Department of Subways for review.

If you have any further suggestions, you may contact Customer Services at (718) 330-3322, from 6:00 a.m. to 10:00 p.m., daily, or write to Customer Services at 2 Broadway, Room A11.146, New York, NY 10004.

We take the concerns of our customers very seriously and thank you for having taken the time to contact us.

Pedro M. Mojica
Associate Transit Customer Service Specialist
Know before you go, use Trip Planner

25 October 2009

Japanese kanji vs Chinese characters

I was going through my receipts from Tokyo tonight. I found this mysterious receipt from 領収証書 which had a line item for 70円普通切手. I couldn't figure out what this 切手 was. It means "cut hand" in Chinese, but thanks to my new Besta CD-863 electronic dictionary with 13 languages, I eventually figured out that 切手 means postage stamp in Japanese!

22 October 2009

Link of the day: Lifehacker on encrypting your data

The post is from 3 years ago, but the instructions are still good. I just encrypted all my personal info, following the instructions in the post. If you have sensitive data on your computer like passwords, serial numbers, addresses, etc, do yourself a favor and encrypt it. If only people had encrypted those stolen laptops with Social Security numbers on them...

21 October 2009

Link of the day: Our internet traffic goes through just a few hands

According to Wired, most of our internet traffic now goes through limited hands, including Google.

Photography tip: Use an ExpoDisc to set white balance on your point-and-shoot camera

One of the ubiquitous hassles in digital photography is achieving the correct white balance. I bought an ExpoDisc originally to do quick white balancing for my hockey dSLR shots.

A few months later, I was getting sick and tired of crappy white balance on my point-and-shoot camera (a Canon SD870 IS Powershot). I tried a gray card but it didn't work at all. Then I decided to put the ExpoDisc over the camera lens and use that to set white balance, using the camera's custom white balance function. Lo and behold -- perfect white balance!

What I learned:
  • You use the ExpoDisc to do white balancing for both dSLR and point-and-shoot cameras. All you need is the ability to set up a custom white balance profile in your particular point-and-shoot camera.
  • Getting the white balance correct is especially crucial for point-and-shoots since most point-and-shoot cameras can only save photos in JPEG and not RAW. It is very difficult to adjust the white balance in a JPEG.
  • Since the lens of the point-and-shoot camera is so small, you can use the smallest and cheapest ExpoDisc (52 mm filter size).
  • Unless you have special needs, use the neutral ExpoDisc.
  • The ExpoDisc is so small and light that you can bring it anywhere. Plus, it's much more durable than a gray card. Not quite as small as a gray card, but that's no big deal unless you're one of those people who likes to count grams.

20 October 2009

My favorite LaTeX font

My favorite LaTeX font is the so-called "palatino." Apparently, it's not really palatino, but a clone. Still, I use it on CVs and resumes to impress people. I especially love the "old style" numbers where the "6" and "8" are shifted up. It's hard to find information about this font. The only substantive page I found was from the LaTeX font catalogue.