Kevin's random thoughts » random

Doing the MPG math

kbullock — Wed, 20 Aug 2008 03:58:00 +0000

Suppose you had a household with two cars, and each car needs to be driven 10,000 miles per year. One car consumes 34 MPG, and the other car consumes 18 MPG. Since gas is expensive, you want to replace one car. Because of utility constraints, you have two choices:

Replace the 34 MPG car with a 50 MPG car — a 16 MPG improvement

Replace the 18 MPG car with a 28 MPG car — a 10 MPG improvement

Which car replacement would save you the most gas? … When you run the numbers, replacing the 34 MPG car with a 50 MPG (a 16 MPG improvement) car saves you 94.1 gallons per 10,000 miles, whereas replacing the 18 MPG car with a 28 MPG (a 10 MPG improvement) car saves you 198.4 gallons per 10,000 miles — more than double the savings. … a textbook case for how common wisdom can fail the common person.

From this blog post (h/t MAKE blog).

It’s an interesting point, and a problem that’s avoided by the metric measurement of gas mileage in L/100km (volume over distance). What we really care about is either (a) how much gas we’re really using for the distance we need to drive, and thus how much money we’re spending on it; or (b) how much particulate matter and noxious gas we’re putting in the air. Both of these are related to the volume of gas used.

Even so, the example above presents something of a false choice. Utility constraints, yes, but replacing an 18 MPG car with a 34 MPG car is still better than replacing an 18 MPG car with a 28 MPG car. Using the right grade gasoline and driving for better mileage also help, no matter what vehicle you drive.

Geeks, nerds, and dorks

kbullock — Wed, 31 Oct 2007 01:56:00 +0000

If you’ve ever wondered what the difference is between a geek, a nerd, and a dork, or if you never realized there was one, here it is:

The Mac is made for dorks. Linux is made for geeks. Windows is made for nerds.

Give a man a thought…

kbullock — Tue, 19 Sep 2006 20:22:00 +0000

I often hear teachers (in the most general, not strictly professional, sense) and others complain about our educational system’s failure to teach people to think. Viz. specifically this rant by the venerable[!] Dr Edsger Wybe Dijkstra.

But in my analysis of such sentiments, I’m forced to ask, how does one person teach another to think? That is, how can I convince another person not to accept at face value what I or someone else says, and instead analyze, break down, understand and reconstruct the knowledge being communicated?

This is an earnest question; I’ve never yet found a way to do it, despite years of trying. It’s also an important question, as the oft-stated goal of education is to teach people to think and deduce and discover for themselves, not to blindly follow the rubrics they’ve been handed.

Give a man a thought, you teach him for a day. Teach a man to think…

Link roundup

kbullock — Wed, 28 Dec 2005 10:33:00 +0000

Here’s my picks of the most interesting articles in my RSS feeds from the past few days. (I’ve made several updates since I first posted this.)

        

        From Las Vegas Prepress:

XML Matters: The Web ain’t just for 2D any more

From boingboing:

A roundup of further info on the Bush-authorized NSA domestic spy ops, with Google-powered satellite photos and everything! Follow-up to this previous post.

From slashdot:

Security Focus Interviews Damien Miller

One of the OpenSSH developers. 4.3 will add full tunneling, i.e. VPN over SSH!
The Mythbusters Answer Your Questions
Sony DRM Installed Even When EULA Declined
Quantum Trickery – Einstein’s Strangest Theory

Link to NY Times story based on the discovery from NIST I wrote on here. An interesting layman’s summary of the weirdness of quantum mechanics. NYT story unfortunately requires login.
Fraud Alleged at Red Cross Call Centers (via this article)

After the hurricanes, I dropped chunks of change in the direction of two charities, the Red Cross and Episcopal Relief & Development. One always hopes that one’s giving will be met with ethical behavior, but it ain’t necessarily so.

From treehugger:

miniHome: The Green Prefab Modern Trailer

There’s a little squishy spot in my heart for trailers, having lived in a trailer park for most of a year in college. This looks stylish to boot. Wonder how it holds up in a tornado.
Wind Power Responding to Global Economic Forces

In which China’s environmental development erodes our economic excuses for not using green energy.

Legare Furniture

kbullock — Thu, 22 Dec 2005 09:11:00 +0000

Found via TreeHugger, which I found via boingboing: http://legarefurniture.com/

Now I just wish they made coffee tables. I also wish I hadn’t just bought a TV stand from Ikea.

Schrödinger’s Ion(s)

kbullock — Mon, 19 Dec 2005 06:02:00 +0000

NIST Physicists Coax Six Atoms into Quantum ‘Cat’ State

BOULDER, Colo. — Scientists at the Commerce Department’s National Institute of Standards and Technology (NIST) have coaxed six atoms into spinning together in two opposite directions at the same time, a so-called Schrödinger “cat” state that obeys the unusual laws of quantum physics. link

As those of you who know me already know, I’m deeply intrigued by the weirdness of quantum physics, so when I stumbled across this story on NIST’s site I was delighted. Like a little kid.

DEATHMATCH: Passat doors vs. freezing rain

kbullock — Thu, 15 Dec 2005 11:28:00 +0000

A couple weeks ago when we had a round of freezing rain, I wasted much of an evening trying to get my car door closed (I got it open just fine, but the latch got stuck). I tried futzing around with the lock for hours with a coat hanger, no luck. Tried slamming it repeatedly to unjam the mechanism, no luck.

        

        Finally I just went outside, Game Boy in hand for meanwhile amusement, sat in the car, fired up the engine, kicked the defroster on full blast at full heat, and let it sit and bake. After about 20 minutes (total guess, this was a couple weeks ago and I wasn’t timing it) of Tetris, I heard the mechanism click and voilà, the door latched shut again.

In the process, I googled to see if others had had the same problem, and found this thread via Google Groups—apparently the locking mechanism in the Passat has this issue :/ Looking around now, I also see this link to a more permanent (and more hackish) fix.

Outside of the door issue though, the Passat is running great. So nice to be driving a manual again. *So* nice.

DEATHMATCH: Britannica vs. Wikipedia

kbullock — Wed, 14 Dec 2005 10:53:00 +0000

The journal Nature have done a study of error frequency in Wikipedia and Britannica, and just published their results:

http://www.nature.com/nature/journal/v438/n7070/full/438900a.html

Turns out Wikipedia is only slightly less accurate than Britannica, at least on matters within Nature’s area of expertise.

        

        Especially interesting following the USA Today furor over a spurious entry about a retired journalist. I think this is a full list of the articles, editorials, and letters they ran on the subject:

http://www.usatoday.com/news/opinion/editorials/2005-11-29-wikipedia-edit_x.htm http://www.usatoday.com/tech/news/techpolicy/2005-12-05-wiki-rules_x.htm http://www.usatoday.com/tech/news/techpolicy/2005-12-06-wikipedia-truth_x.htm http://www.usatoday.com/tech/news/2005-12-11-wikipedia-apology_x.htm http://www.usatoday.com/news/opinion/editorials/2005-12-08-letters-wikipedia_x.htm

Also interesting as we’ve been debating the merits of converting one of our sites at work to a Wikipedia-style maintenance model, and some of the staff have brought up concerns of accuracy, defacing, etc. I find it at least passingly interesting that Wikipedia have begun requiring you to create an account before editing. I’m surprised they hadn’t done so before actually.

Passat!

kbullock — Thu, 03 Nov 2005 14:04:00 +0000

I will be acquiring a ‘96 VW Passat in the next few days. Yay! My supervisor’s partner is selling it pretty cheap because she just got a new Honda Element, and I can sell my current car to make up the entire purchase price.

It’s a five-speed manual with a 6 CD changer, moon roof, leather, heated seats—in short, my dream car. I’m hoping to go pick it up tonight.