DnT Seminar (09/02) @ MOE Edutorium on 19/11/2009

Recommended Reference Books

1. Deconstructing product design : Exploring the Form, Function, Usability, Sustainability, and Commercial Success of 100 Amazing Products
Author William Lidwell and Gerry Manacsa
Publisher Beverly, Mass. : Rockport Publishers, 2009.
NLB (Not ready for loan yet)

1A. Title Universal principles of design : 100 ways to enhance usability, influence perception, increase appeal, make better design decisions, and teach through design
Author Lidwell, William. Kritina Holden, Jill Butler.
Publisher Gloucester, Mass. : Rockport, c2003.
NLB (Central)

2. Design for Environment, Second Edition: A Guide to Sustainable Product Development: Eco-Efficient Product Development

2A. Title Design for environment : creating eco-efficient products and processes
Author: Joseph Fiksel, editor.
Publisher New York : McGraw-Hill, c1996.

3. Title The green imperative : ecology and ethics in design and architecture
Author Papanek, Victor J.
Publisher London : Thames and Hudson, c1995.
NLB (L.K.C Reference ONLY)

4. Title What is product design?
Author Slack, Laura.
Publisher Singapore : Page One, 2006.
NLB (Jurong R./W., Central)

Extra search:

A5. Title Experimental eco- > design : architecture, fashion, product
Author Brower, Cara. Mallory, Rachel, Ohlman, Zachary
Publisher Mies, Switerland : RotoVision, c2009.
NLB (Jurong R./W., Central)

Suggested Websites

• Design Process. Design Stage

http://ahwong.com/comics.html (free PDF)

• The Electronics Club

http://www.kpsec.freeuk.com/index.htm

• Others

http://technologyreview.com/

http://www.economist.com/sciencetechnology/

http://singaporedesignfestival.com/designfest09/

Which one is cheaper, Evian water or petrol?

> Guess you did never think about that
> All these examples do NOT imply that petrol is cheap; it just illustrates how outrageous some prices are. You will be really shocked!
> Think a liter of petrol at $1.60 is expensive? (some time in June 2009, in US$)
> This makes you think, and also puts things into perspective.
> Can of Red Bull, 250ml, $2.95 ... $11.80 per litre!
> Robitussin Cough Mixture, 200ml, $9.95 ..... $199.00 per litre!
> L'Oreal Revitalift Day Cream, 50ml, $29.95 ...... $599.00 per litre!
> Bundy Rum, 1250ml, $51.00 .... $40.80 per litre!
> Visene Eye Drops, 15ml, $5.69 .... $379.00 per litre!
> Britney Spears Fantasy Perfume, 50ml, $29 .... $580.00 per litre!
> And this is the REAL KICKER.
> Evian water, 375ml, $2.95 ...$7.86 per litre! $7.86 for a litre of WATER!!
> And the buyers don't even know the source> (Evian spelled backwards is NAIVE!!)
> Ever wonder why computer printers are so cheap?
> So they can hook you for the ink!!
> Someone calculated the cost of the ink at, you won't believe it but it's true; $1,040 a litre. $1040.00 A LITRE!!!
> So, the next time you're at the pump, be glad your car doesn't run on> water, Red Bull, Robitussin, L'Oreal or, God forbid, Printer Ink
>> MORAL OF THE STORY IS, DO NOT COMPLAIN IF PETROL PRICE INCREASE!!!

Statistics 101

1. Racial Bias

When officers reported knowing the race of the driver in advance, 66 percent of the drivers stopped were black, compared with 45 percent when police reported not knowing the race of the driver in advance, according to the RAND study. (This is a report done in Oakland Police, USA, in 2004)

2. Hit-and-Run Accident (Fictional example proposed by the psychologists Amos Tversky and Daniel Kahneman in the early 1970s)

A certain town has two taxi companies, Blue Cabs and Black Cabs. Blue Cabs has 15 taxis, Black Cabs has 85 (slight variations do exist, e.g. some use 75 instead of 85). Late one night, there is a hit-and-run accident involving a taxi. All of the town's 100 taxis were on the streets at the time of the accident. A witness sees the accident and claims that a blue taxi was involved. At the request of the police, the witness undergoes a vision test under conditions similar to the those on the night in question. Presented repeatedly with a blue taxi and a black taxi, in random order, he shows he can successfully identify the color of the taxi 4 times out of 5. (The remaining 1/5 of the time, he misidentifies a blue taxi as black or a black taxi as blue.) If you were investigating the case, which company would you think is most likely to have been involved in the accident?
Faced with eye-witness evidence from a witness who has demonstrated that he is right 4 times out of 5, you might be inclined to think it was a blue taxi that the witness saw. You might even think that the odds in favor of it being a blue taxi were exactly 4 out of 5 (i.e., a probability of 0.8), those being the odds in favor of the witness being correct on any one occasion.

Do you think the witness was reliable?

However, the facts are quite different. Based on the data supplied, the probability that the accident was caused by a blue taxi is only 0.41. That's right, the probability is less than half. It was more likely to have been a black taxi.

How do you arrive at such a figure? Use Bayes Theorem.
Compute the product
P(blue taxi) x P(witness is right),
and divide the answer by the sum
[P(blue taxi) x P(witness is right) + P(black taxi) x P(witness is wrong)].
Putting in the various figures, this becomes the product 0.15 x 0.8 divided by the sum [0.15 x 0.8 + 0.85 x 0.2], which works out to be 0.12/[0.12 + 0.17] = 0.12/0.29 = 0.41.

To look at the problem from another angle:
For the 15 blue taxis, he would (correctly) identify 80% of them as being blue, namely 12. (In this hypothetical argument, we are assuming that the actual numbers of taxis accurately reflect the probabilities.)
For the 85 black taxis, he would (incorrectly) identify 20% of them as being blue, namely 17.
So, in all, he would identify 29 of the taxis as being blue.
Thus, on the basis of the witness's evidence, we find ourselves looking at a group of 29 taxis.
Of the 29 taxis we are looking at, 12 are in point of fact blue.
Consequently, the probability of the taxi in question being blue, given the witness's testimony, is 12/29, i.e. 0.41.

You see, sometimes, our intuitions can be so wildly misleading!

For the case of 15 blue taxis and 75 black taxis, the probability of the same witness of correctly identifying a blue taxi was 12/27 = 0.44.

Blackjack - The Game of 21

First of all, I am not promoting gambling here. I am definitely against gambling, whether or not money is involved. I am promoting the understanding of probability.

How is Blackjack or 21 played?

Each player plays his hand independently against the dealer. At the beginning of each round, the player places a bet in the "betting box" and receives an initial hand of two cards. The object of the game is to get a higher card total than the dealer, but without going over 21 which is called "busting", "breaking", or many other terms. (The spot cards count 2 to 9; the 10, jack, queen, and king count as ten; an ace can be either 1 or 11 at the player's choice). The player goes first and plays his hand by taking additional cards if he desires. If he busts, he loses. Then the dealer plays his or her hand. If the dealer busts, he loses to all remaining players. If neither busts, the higher hand total wins. If a player ties with the dealer the hand is a "push" and the player's bet is returned.

What do you think is the cut-off point for the dealer representing the casino?

The answer is 17! Yes, 17 Again! (Not the movie though)

If the dealer has less than 17, he must hit. If the dealer has 17 or more, he must stand (take no more cards), unless it is a "soft 17" (a hand that includes an ace valued as "11," for example a hand consisting of Ace+6, or Ace+2+4). With a soft 17, the dealer follows the casino rules printed on the blackjack table, either to "hit soft 17" or to "stand on all 17's."

The Number Sense - Benford's Law

"Would you like to try a bet?

Open a book (any book) at random and note the first digit that your encounter.

If this digit is either 4, 5, 6, 7, 8, or 9, you win $10.

If this difit is either 1, 2, or 3, I win $10. "

Do you think your winning odds (chances) are higher than mine?

I read this in the booked " The Number Sense: How the Mind Creates Mathematics" by Stanislas Dehaene. (Published in 1999, p. 113)

If we keep on playing for a long period, say the running time of a typical movie (2 hours), you would almost always lose. We shall look at the statistics researched by many scientists and mathematicians.

Benford's law (named after physicist Frank Benford), also called the first-digit law, states that in lists of numbers from many (but not all) real-life sources of data, the leading digit is distributed in a specific, non-uniform way.

Measurements of real word values are often distributed logarithmically (or equivalently, the logarithm of the measurements is distributed uniformly).

This counter-intuitive result has been found to apply to a wide variety of data sets, including electricity bills, street addresses, stock prices, population numbers, death rates, lengths of rivers, physical and mathematical constants, and processes described by power laws (which are very common in nature). The result holds regardless of the base in which the numbers are expressed, or the units the measurements are taken, although the exact proportions change.

Income tax controllers use them to check those who are dishonest about their declaration. Benford's Law is also employed to check possible fraud cases in general election, e.g. 2009 Iranian Election.