Friday, August 22, 2008

11:22 pm

General 18: Web findings

Edit 1 (23/8 10.12pm): No digit in Spore NRIC identifies gender
Edit 2 (26/8 10.30pm): The NRIC creator is not a computer programmer.
Edit 3 (28/8 11.11pm): Added warning to NRIC checker.

As most of you would have already known, I surf the net and play with my com alot. Since the prelims are drawing close, I might as well share with all of you some of the interesting findings I have came across in the last few weeks before I temporarily cease my posting.

1. Whats behind the NRIC number?
2. The mathematics of elections
3. NASA's VASIMR engine
4. (S)VTOL aircraft
5. Windows history and blunder + silly promo video


1. NRIC number

Every Singapore citizen and permanent resident is assigned a unique personal National Registration Identity Card number. But how many of you know how the number is derived?

The most common knowledge is that the last last two digits of the birth year are the first two numbers. Numbers are generally assigned continuously throughout the year so those born later have a larger number.

The lesser known ones are that the males have the odd last digit and females have an even one. Don't believe? Check with your family! wjc pointed out my mistake here. It turns out the above applies to Malaysia only. Sorry for the error.

To avoid problems for people living over 100 years in the future, those born in year 2000 and after are assigned the "T" prefix instead of the synonymous "S" prefix.

What about the last letter then? Here's what this section is about.

Its not commonly known that the last letter actually serves as a checkpoint verification code to ensure that the NRIC number is valid. A algorithm called Modulo 11 processes the 7 numbers and generates a checkpoint alphabet.

A local computer programmer writer Gangasudhan used this algorithm to produce a downloadable spreadsheet which can compute the checkpoint letter. Details are in his blog. A simplified explanation to how this algorithm works is here.

Download and give it a try! The same logic is also used for vehicle registration numbers.

Warning: Do not have the misconception that this tool can be used to verify the validity and existence of an IC number. This spreadsheet merely computes the last letter based on the information you provide. For a more reliable tool, use ICHECK provided by ICA.


2. The mathematics of elections

Statistics such as distributions and regression calculations have just been taught for both J2 NYJC H1 and H2 Maths. It may appear mundane and boring to some for those who cannot see much real life applications for it. Well, I found one now!

In his yawningbread blog, local social activist Alex Au wrote in March this year about his mathematical research on the GRC system in Singapore and how it seems to be skewed towards the ruling party. The paper is divided into two parts, Part 1 and Part 2.

Normal distributions-one of the cornerstones of statistics we are studying now, features heavily in his calculations. I can't say much more except to ask you to read it. In summary, it offers an interesting insight against the conventional racial representation idea pushed forward by the government.


3. NASA's VASIMR engine

Currently rocket technology is based on solid fuel for Americans and to a certain extent, liquid fuel for Russians. These technologies are designed to be used impulsively for a short period of time. For longer missions, rockets have to be turned off and the spacecraft has to rely purely on its momentum to reach its destination.

This is inefficient as the final velocity achieved is not very high due to the only short acceleration bursts. There is also a safety risk of rocket fuel igniting while in flight. A different technology has to be developed for long term space travel.

Here is where NASA's VAriable Specific Impulse Magnetoplasma Rocket (VASIMR) technology comes in. It is still in a prototype stage though. View the two videos below to find out more.

Intro to VASMIR.

Conceptual manned mission using VASMIR.

A recap addition. A video I saw when a NASA scientist came to NYJC.

In layman terms, electric fields heat gas particles to plasma and magnetic fields eject a fast stream of plasma ions from the engine. Although the force produced is small, this engine is designed to be utilised for up to years. The cumulative effect over this time frame will allow the spacecraft to attain a speed far greater than conventional rocket engines.


4. (S)VTOL aircraft

Other than computers, jet airplanes have also fascinated me since I was young. This is particularly so for those that can Vertical TakeOff and Land (VTOL). For jet aircraft, the only successful ones are the British Harrier Jump Jet, the (retired) Soviet Yakovlev 38 and the prototype JSF F-35 (B-variant). The tiltrotor Bell V-22 Osprey seems to be the only turboprop aircraft with VTOL.

Detailed intro into Harrier by Discovery Channel (9 mins)

Documentary of F-35B (4.5 mins)

Views into F-35B engines. (subset of above) (1 min)

Yak-141 and Yak-38 in almost all scenarios (2min)

The "S" prefix is for "short". If the planes are fully armed, they are too heavy to takeoff vertically but can attempt a normal takeoff with a much shorter runway than normally required. Sadly, I could not find any videos that show the F-35 progress directly from a vertical takeoff to normal flight as proof although it is assumed it can.

It is interesting to note that Singapore is in the F-35 Joint Strike Fighter programme as a security cooperative and is considering to acquire 100 of these in future. Though, we are unlikely to get the SVTOL variant. (F-22 Raptors are out of the picture!) As to whether its a waste to purchase so many if at all, the debate should be conducted elsewhere.


5. Windows history and blunder

More than 90% of the world's computer run on the Microsoft Windows operating system. The fancy Aeroglass effects some of you take for granted in Windows Vista has certainly come a long way since Microsoft attempted to simplify computing for general users. (Although it is debatable how many innovations were actually done inhouse.)

History of Windows from 1.0 to XP (Vista not included)

Notice Windows 3.1 and Windows 98SE? I currently have them installed in my com under Virtual PC 2007.

Windows 98 blunder

This was one of Bill Gates's greatest hoohas during his career in Microsoft since its inception. He was giving a pre-launch presentation on Windows 98 (First Edition) when disaster striked. The infamous Blue Screen of Death appeared just as his assistant plugged in a scanner to showcase its Plug-and-Play capabilities.

Really embarrassing for the richest man in the world. As many of the computer specialists in the era wrote, Plug-and-Play worked so poorly, more often than not, it was Plug-and-Pray. Thankfully, with the stability of the NT kernel in Windows 2000 and up, we are unlikely to see a repeat of this problem anymore.

To end off in a happier fashion, hope this silly advertising video for MS-DOS 5 (before Windows) puts a smile on your face.

Finally, I hope you enjoyed this "educational" post of mine.

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2 Comment(s)

Hi there. This is a good, comprehensive article and I am sure many readers would have benefitted - and will benefit - from it.

Thank you for mentioning me in the article and including a screenshot of the nric-checker as well. However, I am hardly a 'computer programmer' and actually laughed out loud when I read that description, haha.

No, I am just a regular bloke who has the ability to understand things a bit better and so was able to (painfully) create the excel spreadsheet. In fact, I had to amend the document a few times to get it right and, without the help of other helpful souls not unlike yourself, my checker would have inherent errors.

Once again, I am humbled and honoured to have been cited in this entry and bless your good heart!

By Blogger Ganga, at 26 August 2008 at 8:14 pm 


Thank you! The last thing I expected was you to personally tag here!!!

For accuracy purposes, I have replaced my description with the one in your blogger profile which is "writer". Hope you don't mind. Actually, I first saw your tool being described in my paper which I seen you have posted. Then I felt I wanted to further raise its publicity yo my friends.

The honour is mine for "attracting" your attention here. What you have done is of great service to the web community. I should be the one thanking you!

By Blogger yeokm1, at 26 August 2008 at 10:43 pm 


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