Sunday, February 28, 2010

Thursday, February 25, 2010

Mark Twain on risk analysis

Another post blatantly stolen from Schneier.  It's just so funny, and apt since I'm reading a lot about risk for my upcoming job.  His blog is here.


From 1871:
I hunted up statistics, and was amazed to find that after all the glaring newspaper headings concerning railroad disasters, less than three hundred people had really lost their lives by those disasters in the preceding twelve months. The Erie road was set down as the most murderous in the list. It had killed forty-six—or twenty-six, I do not exactly remember which, but I know the number was double that of any other road. But the fact straightway suggested itself that the Erie was an immensely long road, and did more business than any other line in the country; so the double number of killed ceased to be matter for surprise.By further figuring, it appeared that between New York and Rochester the Erie ran eight passenger trains each way every day—sixteen altogether; and carried a daily average of 6,000 persons. That is about a million in six months—the population of New York city. Well, the Erie kills from thirteen to twenty-three persons out of its million in six months; and in the same time 13,000 of New York's million die in their beds! My flesh crept, my hair stood on end. "This is appalling!" I said. "The danger isn't in travelling by rail, but in trusting to those deadly beds. I will never sleep in a bed again."

School laptop spying

This is frightening.  School officials could turn on the laptop camera of school-issued laptops and used this capability to spy on students at home.  (From Bruce Schneier's blog.)

Wednesday, February 24, 2010

My favorite T-shirt logo

Spotted in the Whole Foods parking lot: "It might look like I'm doing nothing, but at the cellular level I'm really quite busy."

A blessing undisguised

I'm reading the latest edition of Strunk and White.  Here are a few nice lines:

* It is an old observation that the best writers sometimes disregard the rules of rhetoric.  When they do so, however, the reader will usually find in the sentence some compensating merit, attained at the cost of the violation.  Unless he is certain of doing as well, he will probably do best to follow the rules.  After he has learned, by their guidance, to write plain English adequate for everyday uses, let him look, for the secrets of style, to the study of the masters of literature.

* All through The Elements of Style one finds evidences of the author's deep sympathy for the reader.  Will felt that the reader was in serious trouble most of the time, a man floundering in a swamp, and that it was the duty of anyone attempting to write English to drain this swamp quickly and get his man up on dry ground, or at least throw him a rope.

* Understanding is that penetrating quality of knowledge that grows from theory, practice, conviction, assertion, error, and humiliation.

Note, in the examples above, that when a sentence is made stronger, it usually becomes shorter. Thus, brevity is a by-product of vigor.


* Transpire.  Not to be used in the sense of "happen," "come to pass."  Many writers so use it (usually when groping toward imagined elegance), ...  


* Avoid the use of qualifiers.  Rather, very, little, pretty---these are the leeches that infest the pond of prose, sucking the blood of words.

Thursday, February 18, 2010

Credit card fees

Interesting article about the perverse economics of credit cards.    The article focuses mostly on the distinction between signature debit and pin debit, but the problem seems to apply to the industry as a whole.  To make the discussion clear, here are some definitions:

1) Consumer = a customer of a merchant (e.g. you or me)
2) Merchant = a customer of both a bank and Visa (e.g. WalMart, etc)
3) Bank = a bank that issues credit and debit cards.
4) Visa = a (publicly traded) company that controls the electronic payment infrastructure (e.g. Visa, Mastercard)
5) Card = a credit or debit card

Some axioms:


1) Merchants, banks and Visa want to make lots of money.
2) When a consumer uses a card at a merchant's store, the merchant must pay two fees.
  a) a small fee to use the Visa network (about 5 cents)
  b) a large fee to the consumer's bank, (about 1-3% of the purchase price)
  Visa sets both fees (a) and (b)
3) Visa does not issue cards.   Only banks do that.


Now for some simple inference.

By (1), merchants want low fees, banks want high fees.  By (1) and (2) Visa wants as many consumers
using Visa cards as possible.  By (3) Visa's customers are really the banks, not the consumers.  Visa wants banks to issue more Visa cards.  Therefore, Visa has an incentive to raise their fees, thus attracting banks that want to make those higher fees.

Visa can't set the fees too high or merchants will revolt and refuse to accept cards.  But now Visa and Mastercard are in some kind of reverse competition: who can set their rates the highest without a revolt from merchants.

If this were a free market, one could imagine creating a new Visa-like company (with the associated infrastructure) and drop the bank fee to cover the cost to the banks of supplying the cards.  Here the consumers and merchants benefit from the competition, rather than the banks and Visa.   Unfortunately, the card must be attached somehow to the bank account, and only the bank can do that.  So it seems there is a big problem with this market.  Perhaps this could be circumvented in the future if everyone has a PayPal-like account and all the transactions take place directly over the internet.  I can imagine some kind of authentication device being used, part of a phone say.  Merchants could give a small discount to use the PayPal (non-Visa) system.  The banks could fight this of course, but it seems like a possibility for the future.

Emacs word search

One nice feature of Emacs for editing TeX documents is called word-search.  When you're looking at your typeset document and want to go to a particular place, you can simply do a search for the text around the location.  Unfortunately, you don't know where the line breaks are in the file, and thus this simple strategy will fail.  If you use word-search-forward (or C-s RET C-w WORDS) Emacs will build a regular expression that ignores both space and punctuation and go to the correct spot.  

For example, if the pdf file says

The quick brown fox, jumped over the lazy dog.

but the text file has

The quick brown
fox,
jumped
over the lazy dog.

and you word-search for

"brown fox jumped"

it will jump to the right spot.

Tuesday, February 16, 2010

Typo rant

In this article from the most important newspaper in Indiana, there are two typos in three adjacent words.  Do they even use spellcheckers in journalism anymore?  I've noticed a number of typos on the NY times website recently, but this one takes first prize.
"D’Ippolito needed 500 signaures of registerd voters in each of Indiana’s nine congressional districts."
I wonder if non-profit organizations like ProPublica will be able to take care of these dinosaurs.

Verizon

This is clearly one of the companies people mean when they rail against large corporations.  I cancelled my service last month to switch to ATT.  Because I cancelled on Jan 15, but my "cycle" began on Jan 12 I was charged a full month of fees.  They're just evil.  As more evidence, a whistleblower recently gave the New York Times damning evidence about how they deliberately design their phones so it's easy to get overcharged by accidentally accessing the internet.  As usual in the US, caveat emptor.

Monday, February 01, 2010

Toyota acceleration

I've been reading about new Toyotas accelerating out of control and killing everyone inside.  (Imagine that the car just starts accelerating and you can do nothing to stop the acceleration.)  I was imagining how scary it must be, and what you're suppose to do when it happens.   Here are the best ideas I've seen.
  1. Turn the engine off.  
  2. Put the car in neutral.
It's obviously hard to remember this when it's happening.  Solution 1 is a bit scary since you would lose your power breaks and power steering.  If you're going fast the steering wouldn't be a big deal, but I'd be nervous about the breaks.  Is there even a physical connection between the break pedal and the actual breaks in modern vehicles?    Solution 1 is problematic for new cars with keyless ignition.  

Solution 2 will destroy your engine, but not you.  A benefit of a manual transmission is that it is easy.  In fact, just push the clutch in.  I'm not sure if it's always possible with an automatic.  I know on my mom's accord there is a locking mechanism to keep you from putting it in reverse when you're moving forward, but I don't think it applies to neutral.  It seems low-tech cars are the way to go.  One reason to stick with my  1998 Civic.