Archive for April, 2008

Steering by idiocy

April 29, 2008 4 comments


A helicopter was flying around Seattle when an electrical malfunction disabled all of the aircraft’s electronic navigation and communications equipment.

Due to the clouds and haze, the pilot could not determine the helicopter’s position. The pilot saw a tall building, flew toward it, circled, and held up a handwritten sign that said “WHERE AM I?” in large letters. People in the tall building quickly responded to the aircraft, drew a large sign, and held it in a building window. Their sign said “YOU ARE IN A HELICOPTER.”

The pilot smiled, waved, looked at his map, determined the course to steer to SEATAC airport, and landed safely. After they were on the ground, the copilot asked the pilot how he had done it.

“I knew it had to be the Microsoft Building because they gave me a technically correct, but completely useless answer.”

(Hat tip to A Normal Backyard, who has been photographing the Spring return of migratory birds to his yard)

Categories: Humor, observations

Theory is practical in practice

April 28, 2008 4 comments

Regarding DOF’s recent post Theory is Practical, I had a real life example of this today.  This week’s problem set in my class was about graphs, and one of the problems reads

Whenever groups of pigeons gather, they instinctively establish a pecking order. For any pair of pigeons, one pigeon always pecks the other, driving it away from food or potential mates.  The same pair of pigeons will always choose the same pecking order, even after years of separation, no matter what other pigeons are around. Surprisingly, the overall pecking order in a set of pigeons can contain cycles – for example, pigeon A pecks pigeon B, which pecks pigeon C, which pecks pigeon A. If A pecks B, we say that A is dominant and B is submissive.
(a) Prove that any set of pigeons can be listed in some order so that every pigeon pecks the following pigeon.
(b) Prove that any set of n pigeons can be listed in some order so that the number of pairs of pigeons where the dominant pigeon appears before the submissive pigeon is at least [some expression]

The concreteness of this problem was designed to help the students understand not only cases where graphs can be applied, but to make the problem easier to understand.  I certainly thought that it would have this effect when I read it, and it seems much less intimidating than “Prove that every orientation of a complete graph has a Hamiltonian path,” which is what the question is “really” asking.  My office hours indicated that it did not succeed in these goals.  This was the question I got asked about much more than any other question, and most students seemed really confused by what the pigeons had to do with the problem, or even what the problem was asking.  It’s interesting to me the amount of confusion which this caused.  The students are still struggling with the basic concepts of graphs, so they had a lot of trouble thinking of the “right” way to abstract the problem, and then on top of that prove things about it.

I’m not sure what the best solution is for all this.  Throughout much of the course, I’ve heard about how the material seems irrelevant to computer programming, and that the material is too abstract.  Should we ignore complaints about the material, and give the students a heavy dose of abstraction, give the applications after students have done the homework (which might lead to frustration when students don’t know what theorems are “for”), or perhaps keep using problems like this.  I don’t know, but it’s certainly interesting to think about.

(This is not to harp on the author of the question, who is a very good teacher.  I think these issues are difficult, and there is no right answer.  I just found the students’ response interesting and noteworthy.)

Categories: Uncategorized

Xubuntu 8.04 on IBM ThinkPad T-21

April 28, 2008 3 comments

You wouldn’t think an eight-year-old laptop would be good for much.  Its PIII processor and paltry 512mb of RAM, plus its puny 30 gig hard drive just don’t add up to a lot of firepower.  This wasn’t a problem until a month ago when a couple new Microsoft patches came out that just bogged it down.  Even a fresh build didn’t help.

But the IBM ThinkPad T-21 is just too good to throw out.  It was a maximally-engineered model with a carbon-fibre frame, a crisp, easy-typing keyboard, and a great screen topped with a titanium lid.  And it was cheap: it sold for three grand when it was new, but I bought for my son a couple years ago for one-tenth that much.

I tried Ubuntu on it but running Ubuntu is a young laptop’s game.  Ubuntu is intended to compete with Windows Vista and it’s really needs a P4 with a gig of ram to run well.  (Vista needs much more)  An older machine like this one needs a lighter, more stripped-down OS.  Then Webs05 sent me this email:

Xubuntu 8.04 is [great]!  There is no other way to put it! So far I am having super amazing results. And I am currently installing it on Katie’s laptop, which means they fixed A LOT of previous issues. Katie’s laptop is the old X23… Anyways, try it out. I am going to be writing a post soon.

Well that’s interesting because the ThinkPad X-23 is a smaller but otherwise very similar machine as far as the operating system is concerned.  And I did try it out, splitting the HD into two primary partitions and putting the /home in the second partition, with / and /swap in the first partition.  It works great, it’s reasonably fast, it suspends well, and the wireless works fine.  It even set up the Broadcom 54g wireless card with no problem. 

Xubuntu is Ubuntu without all the gingerbread; it doesn’t waste CPU cycles trying to be pretty.  And it works: this old laptop has a new lease on life.  I’m putting a new battery in it and giving it back to my son.

One little thing though: do you suppose the Ubuntu people could quite naming their releases things like “Feisty Fawn” and “Gutsy Gibbon”?  It just sounds kind of Disney, like a character on one of their “video-only” kids’ movie releases.  Couldn’t they call it something cool like “Great White” or “Leopard”?  Oh wait, that one’s taken…

Categories: Geeky, Software

Monday Morning Music: SPIN

April 28, 2008 1 comment

Some very funny stuff:

(Hat-tip to Greg Laden)

Categories: music, Reviews

Educational Contraband

April 26, 2008 4 comments

Dana over at En Tequila Es Verdad picked up on something I said in the post about ‘A little thrill in learning’ and took off in a whole different, wonderful direction with it: Educational Contraband.  Go check it out, then think back to your favorite teachers: were they smugglers, most of them?  When you were with them, did you have the feeling you were being let in on a secret?

Categories: Education

Theory is practical

April 26, 2008 3 comments

“Education would be much more effective if its purpose was to ensure that by the time they leave school every boy and girl should know how much they do not know, and be imbued with a lifelong desire to know it.”

- Sir William Haley

I’ve always been interested in math education for the main reason that mine worked out so badly.  As a dyslexic child, I had a difficult time reading numbers (still do) and the first six grades seemed to consist almost exclusively of memorizing tables.  Until that was done, no logic! no problem solving for you!  But since it was almost impossible for me to memorize tables, I grew up believing I was “bad at math”. 

Fast-forward a number of decades.

DOF co-author Lucas, who has some serious math chops, told me he’d rather kids spend a lot of class time understanding one problem very deeply than ploughing through a whole page of the same kind of problems.  And yeah, that sounds right.  He translated that to science with ‘more time on theory than lab work’ and, hmm… I wasn’t sure about that.  Lab work is important, I thought.  Wouldn’t you get theory from lab work?  Well not necessarily…

Along comes this report on ScienceDaily, Concrete examples don’t help students learn math, study finds.  Professors at Ohio State put it to the test and found out, maybe we should be going from theoretical to specific:

A new study challenges the common practice in many classrooms of teaching mathematical concepts by using “real-world,” concrete examples. Researchers led by Jennifer Kaminski, researcher scientist at Ohio State University’s Center for Cognitive Science, found that college students who learned a mathematical concept with concrete examples couldn’t apply that knowledge to new situations. But when students first learned the concept with abstract symbols, they were much more likely to transfer that knowledge, according to the study published in the April 25 issue of the journal Science.

“These findings cast doubt on a long-standing belief in education,” said Vladimir Sloutsky, co-author of the study and professor of psychology and human development and the director of the Center for Cognitive Science at Ohio State. “The belief in using concrete examples is very deeply ingrained, and hasn’t been questioned or tested.”

The words; “hasn’t been questioned or tested” make for low-hanging study fruit.  Common sense often knows a lot of things that ain’t so:

For example, there is the classic problem of two trains that leave different cities heading toward each other at different speeds. Students are asked to figure out when the two trains will meet.

“The danger with teaching using this example is that many students only learn how to solve the problem with the trains,” Kaminski said. “If students are later given a problem using the same mathematical principles, but about rising water levels instead of trains, that knowledge just doesn’t seem to transfer,” she said.

“It is very difficult to extract mathematical principles from story problems,” Sloutsky added. “Story problems could be an incredible instrument for testing what was learned. But they are bad instruments for teaching.”

“That knowledge just doesn’t seem to transfer.”  This lines up with my experience in technical support.  The most challenging client is the one with a yellow legal pad next to their keyboard.  They ask how to do something; I already know they are NOT interested in the theory behind it.  They want an exact formula – “Click here, then click there, type these words in, press enter…”  They’ll write down every step word for word.  But they can’t transfer that ‘knowledge’ to new situations.

In tech support, you’ll get the lion’s share of phone calls from clients who are overly focused on the immediate problem. To them it seems extraneous to learn why something happens.  But as soon as any little thing changes, they’re reaching for the phone again.  When I’m with them, I want to say; “Put your pen and your legal pad down and let’s just talk a little about web pages and servers and stuff.”

Teaching is a kind of tech support.  Maybe the way we educate now is too heavy with “click here, type these words in…”  Arthur C. Clarke said the ideal classroom was a log, with a teacher at one end and a student at the other.  They could talk, explore ideas, figure things out and be able to adapt when things change.  But the school district has a number of board members who want to make sure there’s no evolution or sex education on the log.  And the parents come in to yell at the instructor for asking mean questions that made the student stay up half the night thinking about them. Then the Department Of Education shows up and starts insisting on standardized tests and whether the students know enough random trivial facts.  Now the kid goes home with a sheaf of homework to be sure he can spew out those facts come NCLB test time. Education just ain’t the same on the log anymore. 

Categories: Education

Lots of accounts deleted

April 25, 2008 6 comments

I just deleted over a hundred ‘Pending Accounts’ and some current accounts which appeared to be from spam domains.  However, my mouse hand is not steady and it is not always easy to tell,  so if I accidentally deleted your legitimate account, please accept my abject apology and re-create your account.  Thanks!

By the way, registering an account is like a VIP card when you make comments – log in and you don’t have to wrestle with that “captcha” thing.  The other advantage of registering is that your blog URL is embedded in your nickname, which elevates your Google ranking!  I do not use the account information for any other purpose and your email does not display on the page.

UPDATE: I just found out that the ExpressionEngine system sent out a nastygram with the non-approval.  I didn’t know it would do that, but thanks to one of my accidental deletions for letting me know.  I just found that template and changed it to something nicer (and inviting correction) but my apologies to anyone who received one from the EE system.

Categories: Blogging, Geeky

The more things change

April 25, 2008 7 comments

Just in case you’re wondering how long the Republicans have been using the same script…

“…Did the Democrats, asked Republicans, intend to give Puerto Rico back to Spain?  Or forget that American lives had been lost in the Philippines?  Weren’t Democratic anti-imperialists like Stevenson, as President McKinley asked, similar “to guerrillas who shoot at American soldiers?”

Sensitive to the concentration of power that accompanied war, Stevenson informed Bryan that imperialism must remain the central issue of the campaign.  His constant subject, after his brief complaints about high tariffs, “which secure unjust advantages for the few”, remained “the greedy spirit of commercialism which has embroiled our government in an unnecessary war, sacrificed valuable lives and placed the American Republic in deadly antagonism to our former allies in their effort to secure their liberties.  For the first time in our history we are boldly confronted with the question of imperialism – the spirit of empire.”

Jean H. Baker, The Stevensons, W.W. Norton & Company, p. 176, on the 1900 presidential race between William McKinley and William Jennings Bryan

Categories: Politics

“A little thrill in learning”

April 25, 2008 6 comments

It’s the fun surprises you find on the Interwebs:

The big switchoff
Most people don’t think much about what’s inside a switch.  If you take one apart, you’ll see some kind of spring-loaded contacts, usually copper.  The plastic body hides a small spark that happens every time you throw the switch. Then there are self-operating switches; circuit breakers that switch off automatically when the load exceeds a preset number of amps, say ten or twenty. 
But what if the breaker has to break a circuit carrying a thousand or two thousand amps, and maybe ramp up the voltage to, say, 35,000 volts?  Then there’s the possibility of very rapid erosion or even explosive vaporization of the contacts. Cajun published a picture of one such breaker switch and I asked him “How does that thing work?”  His response was a fascinating post ‘You ask, we answer’.  Be sure to click through to the original post with the pictures too.  (Some innovative broom repair techniques thrown in at no extra charge) If you’ve ever stood looking through the fence at a power substation and tried to dope out how it all works you’ll enjoy it as much as I did. 
That thing you have seen all your life and always wondered about
Les at Stupid Evil Bastard says; “I always get a little thrill from learning the history of things like the Giant Tire. It’s been there my entire life and I never fail to think about it whenever I drive past it, but only after 40 years have I ever been in a spot to learn about it.”
Yes, a giant tire!  And by ‘giant’, I mean big enough to hold a ferris wheel inside.  See his post; So that’s what the Uniroyal giant tire once looked like! 

It’s my contention that what’s missing from our politically-correct, NCLB-driven schools today is pretty much any possibility at all of ‘a little thrill in learning’.  It happens, but good teachers have to wedge it into the cracks where they can.  Yesterday morning I was surprised by an article about math education and I’m still turning it over in my head.  Will post about it tomorrow morning after breakfast.

What kind of things do you look at in everyday life, and wonder about?

Categories: Science & Technology

Iraq Veterans Against The War (updated)

April 22, 2008 13 comments

Iraq Veterans Against The War visited our campus today with a display of boots and shoes.  Lined up in neat rows like tombstones, decorated with a name and in some cases a photo or a medal, each pair of boots belonged to an Illinois soldier who didn’t make it home.  There were also circles of shoes, from Iraqi civilians of all ages.  Veterans were on hand to reflect on the war.

What could I say that is not said by a little pair of fuzzy booties that belonged to a child?  Or by a pair of boots that belonged to a soldier, decorated with his high school graduation picture?  It is bad enough when there is an arguable purpose to it all, but this war is for nothing.  It is a personal vendetta of our codpiece-in-chief.

Mark Twain said; “History does not repeat itself.  But it rhymes.”

Boots in a row

Civilian shoes
Civilian shoes
Civilian shoes
Overview; boots in foreground, civilian shoes in background

Categories: defense, Politics