Friday, November 27, 2009

Three "timepass" links!

Timepass links for the weekend.

1. Life (via this and this place)

2. Fox News needs a math lesson? (via FlowingData)


3. A fascinating blog on the "meandering of rivers". One very interesting tidbit towards the end of the article is "self-similarity". Apparently some universality underlies the meandering of rivers and streams.

It seems that the wavelength "lambda" is approximately 11*w and the "radius" is approximately 2.3*w, where "w" is the width of the stream

Wednesday, November 25, 2009

I love craigslist

I once owned eBay stock, and they were scared of craigslist.

Similar to Microsoft's fear of the open-source movement.

This inspiring article from Wired magazine, tells you why it would be great to work for this company, and why its competition just can't figure it out.
... what you see at the most popular job-search site: another wasteland of hypertext links, one line after another, without recommendations or networking features or even protection against duplicate postings. Subject to a highly unpredictable filtering system that produces daily outrage among people whose help-wanted ads have been removed without explanation, this site not only beats its competitors—Monster, CareerBuilder, Yahoo's HotJobs—but garners more traffic than all of them combined. Are our standards really so low?
But if you really want to see a mess, go visit the nation's greatest apartment-hunting site, the first likely choice of anybody searching for a rental or a roommate. On this site, contrary to every principle of usability and common sense, you can't easily browse pictures of the apartments for rent. Customer support? Visit the help desk if you enjoy being insulted. How much market share does this housing site have? In many cities, a huge percentage. It isn't worth trying to compare its traffic to competitors', because at this scale there are no competitors.
Each of these sites, of course, is merely one of the many sections of craigslist, which dominates the market in facilitating face-to-face transactions, whether people are connecting to buy and sell, give something away, rent an apartment, or have some sex. With more than 47 million unique users every month in the US alone—nearly a fifth of the nation's adult population—it is the most important community site going and yet the most underdeveloped. Think of any Web feature that has become popular in the past 10 years: Chances are craigslist has considered it and rejected it. If you try to build a third-party application designed to make craigslist work better, the management will almost certainly throw up technical roadblocks to shut you down.
 This is a great article, and reads really well.

Why can't Apple figure the mouse out?

In terms of usability, Apple products like the iPhone and iPod are design icons. Elegance, utility and simplicity rolled into beautiful compact devices.

Many years earlier, in 1984, Apple did something similar to the computing world, and brought the GUI and mouse to life (thanks to Xerox). Since those paleolithic days, it has always stuck with a "single-button" mouse, the defense being more buttons are "confusing to novice users", or some crap like that.

That unrelenting stubbornness continues to this day.

In 2006, I bought a MacBook Pro at work, with a single button mouse as shown above. For the most part, I like my Mac, although I prefer a similarly priced Linux machine running Ubuntu.

I never really liked the one button mouse, but out of the compromise that is this life, I forged a working relationship with it.

In other parts of the world, the number of buttons on "mice" have increased, as shown by the five button mouse here (from wikipedia).

Last month, my wife got a new Mac from her workplace, after her old Mac gave her repeated battery problems.

To my surprise and utter disgust, in these spanking new machines, they got rid of the only button left!

And replaced that with a trackpad, instead. So her computer looks like the picture below.

No buttons. See!

The whole trackpad is the button. WTF?

To add to the insult, it now has all the cool features such as zooming using two fingers, borrowed from their iPhone. Personally, I find it extremely annoying, since every time I try to select some text using two fingers (and there is no button to anchor one of the fingers, remember), it thinks I want to zoom.

To think that they wanted to stick with a single button because novice users would be confused.

Heck, I've been using computers for 20+ years, and I am confused with this crap!

Sunday, November 22, 2009

The Forer Effect

I came across "the Forer effect" on this blog (via Abi). As Abi points out on his blog, you should send this "to all your friends/family members/associates who believe in astrology".

The story runs thus:

A psychologist named B. R. Forer apparently gave a bunch of his students a personality test (like a Myers-Briggs test, or one of those stupid Cosmo' surveys), and asked each person taking the test to rate the accuracy of the customized "individual profile" between 0 and 5, ranging from the least to the most accurate.

Unknown to the participants, there was really only one common profile (independent of the choices on the personality test), which read:
You have a great need for other people to like and admire you. You have a tendency to be critical of yourself. You have a great deal of unused capacity which you have not turned to your advantage. While you have some personality weaknesses, you are generally able to compensate for them. Your sexual adjustment has presented problems for you. Disciplined and self-controlled outside, you tend to be worrisome and insecure inside. At times you have serious doubts as to whether you have made the right decision or done the right thing. You prefer a certain amount of change and variety and become dissatisfied when hemmed in by restrictions and limitations. You pride yourself as an independent thinker and do not accept others' statements without satisfactory proof. You have found it unwise to be too frank in revealing yourself to others. At times you are extroverted, affable, sociable, while at other times you are introverted, wary, reserved. Some of your aspirations tend to be pretty unrealistic. Security is one of your major goals in life.

This average score on this and similar studies (repeated a gazillion times) was around 4.2 (pdf original research article, on Scribd).

Our gullibility is shocking, huh?

Here's an YouTube video, for those who don't like to read, or, for those who also like to watch. It's an entertaining video, which shows how little gender, culture, and other elements matter.

If this study was included as a foreword in Linda Goodman's books, I wonder if they would have sold nearly as well.

This has direct implications, not only for "psychic" disciplines, but also on personality test batteries, such as Myers-Briggs.

Friday, November 20, 2009

Buzzwords and Data Visualization

I stumbled upon two interesting links via this blog that I follow:

1. A PhD comics take on buzzwords in scientific literature.

2. Top 10 worst data visualizations in scientific literature. Some of it may be nit-picking, and I am sure like all top-10 lists (or US News college rankings, for that matter) this list is flawed in terms of the "top"-10. But it makes for an interesting read nevertheless.

The "discussion" on each graph is enlightening, particularly since I must have committed some of the same mistakes myself.

One interesting thing I learned was how bad pie charts were. Apparently, we are much better at comparing lengths than areas. I never knew that.

There are some good links on how to present data wisely at the bottom of this link.

Wednesday, November 18, 2009

The Tipping Point

I know I am late to the party, since this popular book by Michael Gladwell was published almost a decade ago. The book attempts to present a synthesis of many disparate ideas to ponder over the question: "Why do some ideas catch fire?", or as he would probably like it phrased "What makes an idea tip?"

The book itself is enjoyable, as it talks about Paul Revere's midnight ride, the Mavens, the Connectors, and the Salesmen, the fascinating rule of 150, Bernie Goetz and how cleaning up graffiti on subway walls reduced crime in New York, Hush Puppies, the stickiness of Sesame Street and Blue's Clues, Peter Jennings demeanor during Ronald Reagan's candidacy, six degrees of separation etc.

He cites a number of interesting social and psychological research studies, and being the master storyteller that he is, beautifully integrates them into his narrative.

I think he makes a great journalist.

However, I think he would make a bad scientist.

This is pure extrapolation from the one data point I am familiar with. The six degrees of separation reference to Stanley Milgram is bad science. He repeats some of the same stuff in his famous article "Six Degress of Lois Weisberg".

The myth suggests that Milgram gave 160 people in Omaha, Nebraska a package that had to be delivered to a stockbroker who worked in Boston, through the smallest number of intermediaries. He found that "chains varied from two to 10 intermediate acquaintances, with the median at five" in his 1967 paper - which apparently is the basis for the "six degrees" supposition. The big problem for me as a scientist was that only 24 of the original 160 chains was completed - and hence the conclusion probably suffers from a heavy survivorship bias.

Milgram carried out an earlier study where starters were from Wichita, Kansas and were supposed to reach a divinity student on the east coast, and the completion statistics there were more miserable. The measurement error must have been quite large to suggest such a strong conclusion.

Sure, we might indeed be separated by six degrees. But Milgram's study does not definitively prove it.

In fact there are other glaring problems with Milgram's study as this very interesting and more academically rigorous article points out.

PS: I swear I wrote this blog a long time ago, and thought that I would publish it later. In the meantime, I bumped into this article by Steve Pinker (via nanopolitan). It is amazing that he comes to the same conclusion towards the end of his book-review:
Readers have much to learn from Gladwell the journalist and essayist. But when it comes to Gladwell the social scientist, they should watch out for those igon values.

Monday, November 16, 2009

Society of Rheology meeting - Madison, WI.

I was in Madison, WI  for my annual pilgrimage to the Society of Rheology annual meeting. Of the several meetings I go (or, have gone) to, this is easily my favorite. It is very focused - I learn a lot, and always come back with ideas to try, things to check, and papers to read.

It is small, fun, very good value for money, and has plenty of good food and drink.

Here are some pictures I took in Madison, when my colleague and I went for a run from our hotel near the state capitol to the University. It is always great to catch fall in the northern states, especially having been away from Michigan for a while.

Friday, November 13, 2009

Interesting Economics/Finance Links

Three interesting links for the weekend.

1. A fascinating article in Vanity Fair on the state of Harvard's endowment (Rich Harvard, Poor Harvard). It's hard for me to really feel sorry, although I know it hurts a lot of innocent bystanders. From the article:
Only a year ago, Harvard had a $36.9 billion endowment, the largest in academia. Now that endowment has imploded, and the university faces the worst financial crisis in its 373-year history. Could the same lethal mix of uncurbed expansion, colossal debt, arrogance, and mismanagement that ravaged Wall Street bring down America’s most famous university?

2. This NYT article (free sign up required) recounts how the governor of India's Reserve Bank, Y. V. Reddy, played it tough during the bubble years, and saved the country from a financial crisis. He seems like the anti-thesis of former Fed-chairman Alan Greenspan, both in action and in popularity. From the article:
Unlike Alan Greenspan, who didn’t believe it was his job to even point out bubbles, much less try to deflate them, Mr. Reddy saw his job as making sure Indian banks did not get too caught up in the bubble mentality. About two years ago, he started sensing that real estate, in particular, had entered bubble territory. One of the first moves he made was to ban the use of bank loans for the purchase of raw land, which was skyrocketing. Only when the developer was about to commence building could the bank get involved — and then only to make construction loans. (Guess who wound up financing the land purchases? United States private equity and hedge funds, of course!)
Seeing inflation on the horizon, Mr. Reddy pushed interest rates up to more than 20 percent, which of course dampened the housing frenzy. He increased risk weightings on commercial buildings and shopping mall construction, doubling the amount of capital banks were required to hold in reserve in case things went awry. He made banks put aside extra capital for every loan they made. In effect, Mr. Reddy was creating liquidity even before there was a global liquidity crisis.

3. An interesting email conversation  (pdf) between Buffett and Raikes, regarding Microsoft and Berkshire (via Reflections on Value Investing).

Dicey puzzle: Solution

The full puzzle statement may be found here.

In short "What are the odds that n=2 v/s n=3 dice are rolled, given that the sum is 7?"


For n=2, there are 6 ways of rolling a 7 (1+6, 2+5, 3+4, 4+3, 5+2, and 6+1), out of a total of 6^2=36 total outcomes.

Therefore p(sum = 7 | n = 2) = 6/36 = 36/216.

For n = 3, there are 15 ways of rolling a 7 (1+1+5, 1+2+4, 1+3+3, 1+4+2,1+5+5, 2+1+4, 2+2+3, 2+3+2, 2+4+1, 3+1+3, 3+2+2, 3+3+1, 4+1+2, 4+2+1, 5+1+1), out of a total of 6^3 = 216 total outcomes.

Therefore p(sum = 7 | n = 3) = 15/216.

Thus, the odds of n = 2 v/s n = 3 are 36/15. That is it is about 2.5 times more likely that n = 2.

What happened? There were more ways of getting a 7 with n = 3?

Wednesday, November 11, 2009

LaTeX equations in Google Documents

I found out from here that I can now type LaTeX equations into Google Documents, and they look pretty nifty too.

I find the look of equations using Microsoft Equation Editor to be truly hideous. Of course you can buy MathType, but why? The native equation editor in OpenOffice is efficient to use, but I still don't like how they look in the document. Despite its age, LaTeX typesets equations beautifully - and there is no reason to discard something good, just because it is old.

Previously, I wrote about how I currently use a plugin called OOOLaTeX, which lets me combine the beauty of LaTeX with the unbeatable price and portability of OpenOffice.

Back to the topic of the post.

It really is easy to use. Just go to Insert->Equation and you can enter LaTeX code directly, or choose symbols from the dialog boxes above.

Here are a couple of screenshots:


I can easily visualize myself using this for presentations.

Sunday, November 8, 2009

Advice from a scientist

I found this article via this blog that I follow.

The advice is commonsensical, which, ironically, makes it a must-read.

Some of my favorite excerpts:
Now for the matter of drive. You observe that most great scientists have tremendous drive. I worked for ten years with John Tukey at Bell Labs. He had tremendous drive. One day about three or four years after I joined, I discovered that John Tukey was slightly younger than I was. John was a genius and I clearly was not. Well I went storming into Bode's office and said, ``How can anybody my age know as much as John Tukey does?'' He leaned back in his chair, put his hands behind his head, grinned slightly, and said, ``You would be surprised Hamming, how much you would know if you worked as hard as he did that many years.'' I simply slunk out of the office!
My own PhD advisor, Ron Larson, is this (Tukey) type of person. Towards the end of my PhD, I realized that I had to do something he wasn't interested in. Barring luck, it is hard to directly compete with him. He is smarter, and works longer hours.

Another quote from the speech:
What Bode was saying was this: ``Knowledge and productivity are like compound interest.'' Given two people of approximately the same ability and one person who works ten percent more than the other, the latter will more than twice outproduce the former. The more you know, the more you learn; the more you learn, the more you can do; the more you can do, the more the opportunity - it is very much like compound interest. I don't want to give you a rate, but it is a very high rate. Given two people with exactly the same ability, the one person who manages day in and day out to get in one more hour of thinking will be tremendously more productive over a lifetime.
There's another trait on the side which I want to talk about; that trait is ambiguity. It took me a while to discover its importance. Most people like to believe something is or is not true. Great scientists tolerate ambiguity very well. They believe the theory enough to go ahead; they doubt it enough to notice the errors and faults so they can step forward and create the new replacement theory. If you believe too much you'll never notice the flaws; if you doubt too much you won't get started. It requires a lovely balance. But most great scientists are well aware of why their theories are true and they are also well aware of some slight misfits which don't quite fit and they don't forget it.

Friday, November 6, 2009

Eric Drexler and Science Education in India

Eric Drexler (a nanotechnologist) wrote an interesting article on his blog about how the subset of visitors to his site from India, chose to visit the more technically meaty topics.

A comment on his post, which I sympathize with, provoked a second article, which sought to understand the previous post in a more nuanced manner.

During the course of reading these articles, I also stumbled upon this interesting YouTube presentation.

I have my own thoughts on this matter, having been a student and educator in both the US and in India, but I will save those for a separate post, later.

Thursday, November 5, 2009

Install LAMMPS with FFTW on your Desktop

Earlier I wrote about how to install LAMMPS and AtomEye on a Desktop without FFTW.

The following document now shows how to download, compile and build the freely available fftw library with LAMMPS to consider electrostatic effects.

Building LAMMPS with FFTW

How to embed a pdf document in blogger?

The idea is like embedding a YouTube video as I remarked earlier. By trial and error, I have come to the personal conclusion that this is going to be my method of choice, from here on.

The steps are simple:
1. Get a Scribd account.
2. Upload your document there, where it is converted into an iPaper format.
3. Look for "Embed Code" - and copy the html code snippet under it.
4. In your Blogger entry, select the "Edit HTML" tab, and go to the place where you want to embed the stuff
5. Paste the html code snippet here.

You should be good to go.

Here is an example.

Wednesday, November 4, 2009

Dicey puzzle

Your friend rolls either one, two, or three dice (n=1, n=2 or n=3). Each die is a normal cube with six sides, displaying a number between 1 and 6. She doesn't tell you what n is, but tells you that the sum of the numbers on the dice is 7.

For example, she could have rolled 4 and 3 with n=2; or perhaps 5, 1, and 1 with n=3 etc. Obviously, n cannot be equal to one.

What are the odds of n=2 v/s n=3 given that the sum is 7?

Answer coming up in a week, but this is an example of simple Bayesian analysis.

Credits: picture from

Monday, November 2, 2009

Knuth, calculus and O-notation

I found an interesting entry on a blog I follow, about a "new" method of introducing calculus, by Donald Knuth. Fundamentally, it involves introducing the big-oh notation to define a "strong derivative", and recovering most results including the Fundamental Theorem of Calculus (see the comments section). The resulting math feels light - like you were doing a back of the envelope calculation.

It seems interesting, and although I am not sure whether that is the magic potion that will enable all my students to master the idea of applying calculus in physical problems.

Personally, I never had a problem with the traditional approach starting with the definition of a limit.