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Sudah berulang kali aku terbingung dengan satu huruf pada nomor siswa (matriculation number) ku. Aku kuliahnya di Nanyang Technological University (NTU), Singapura. Nomor itu terdiri dari 8 angka dan 1 huruf. Aku dan beberapa teman penasaran dengan arti dari 1 huruf itu, menandakan apakah itu?

It has been several times that I am confused with a letter in my university matriculation number. I am studying at Nanyang Technological University (NTU), Singapore. The number consists of 8 numerical digits and one letter. I and several of my friend are curious about the meaning of the letter, what does it mean?

0 3 3 2 9 9 H 0 6
a1 a2 b1 b2 b3 b4 c d1 d2
a b c d

Itu salah satu contoh nomor siswa, 033299H06. Berdasarkan pengamatan yang sederhana, bisa dipastikan bahwa a = tahun mulai kuliah, b = nomor seri (tak perlu urut), dan d = kode jurusan. Namun c itu apa yah?

That is an example of a matric number, 033299H06. Based on a simple observation, it can be assured that a = the year of entering university, b = serial number (not necessarily sequential) and d = course code. But what actually is c?

Kuhabiskan sekitar 1 jam untuk mengambil kumpulan besar data (setelah beberapa hari lalu muncul idenya) (makasih regex, ultraedit, opera, flashget, directory opus) lalu dengan mencari pola-pola yang ada, akhirnya kutemukan rumusnya, hore!

I wasted about an hour to obtain a big collection of data (after I find the idea some days ago) (thanks to regex, ultraedit, opera, flashget, directory opus) then by finding patterns there, finally I found the formula, yippie!

OK, berdasarkan huruf-huruf yang kutemukan, hanya salah satu dari ABCDEFGHJKL yang mungkin muncul. Dengan demikian ada 11 macam. Yang paling masuk akal sih huruf itu merupakan checksum. Dan melihat bilangan itu 11, yaitu bilangan prima, kemungkinan besar rumusnya menggunakan sisa bagi 11. Jadi mari kita asosiasikan A dengan 0, B dengan 1, C dengan 2, dan seterusnya, sampai K = 10.

OK, based on the letters I found, I found that only one of ABCDEFGHJKL that is possible to be the letter. Therefore, only 11 kind of them. I think the most sensible thought is that the letter is a checksum. And seeing that the number is 11, that is a prime number, most probably the formula is using modulus 11. So let's associate A with 0, B with 1, C with 2 and so on, until K = 10.

Ternyata cara yang pertama kali ditemukan salah pada sekitar 1/8 dari data-data yang ada! Terima kasih Ainun Najib atas penemuan kesalahannya!

It is revealed that the method that I published for the first time still gives incorrect results on about 1/8 of the data! Thank you Ainun Najib for finding the incorrectness!

Untuk melihat cara pertama, klik sini.

To see the first method, click here.

Setelah beberapa analisis lanjutan yang terlalu bingung mau gimana diungkapkannya di sini (cara 1), ditambah dengan kebingungan kedua setelah melihat adanya hubungan erat dengan b1 (cara 2), aku temukan kecerahan! Mari kita tentukan h berdasarkan rumus berikut,

After some analysis following that, that is too confusing to know how to explain here (method 1), and I got the second confusion after I see that there was a tight relation with b1 (method 2), I got a light! Lets define h based on the following formula,

h = (5 a1 + 6 a2+ 7 b1 + 4 b2 + 3 b3 + 2 b4 + 9 d1 + 8 d2 + 10) % 11

Untuk contoh di atas, 033299H06:

For the above example, 033299H06:

h = (5 a1 + 6 a2+ 7 b1 + 4 b2 + 3 b3 + 2 b4 + 9 d1 + 8 d2 + 10) % 11 = (5 (0) + 6 (3) + 7 (3) + 4 (2) + 3 (9) + 2 (9) + 9 (0) + 8 (6) + 10) % 11 = (18 + 21 + 8 + 27 + 18 + 48 + 10) % 11 = 150 % 11 = 7

Cocokkan h, 0 adalah A, 1 adalah B, 2 adalah C, dan seterusnya (dengan urutan "ABCDEFGHJKL"), maka 7 adalah H. Tepat, kan! Cukup untuk penjelasannya, udah cape, jika ada pertanyaan, aduan, godaan, keluhan, silakan sampaikan di bawah.

Match the h, with: 0 is A, 1 is B, 2 is C, and so on (with sequence: "ABCDEFGHJKL"), so 7 is H. Correct, isn't it? That's all for the explanation, because I'm tired. If you have questions, complain, temptation, grumple, please tell me below.

 

Written by: yuku

I haven't read the whole article, but I just noticed that the second last sentence in the English translation "That's all for the explanation, I'm tired." doesn't sound too friendly. Hehe.

kitty [sg], 8 Oct 2005, 16:14 reply
The artikel is unexpextedly interesting, at first, I think it would not... but then after I read some of it, it was getting more and more interesting. But then, I wondered, what is 'c' used for?

Lesmanahadi [id], 8 Oct 2005, 17:54 reply
bener nih ?
pengamatan cuma 1 matric card aja apakah cukup ?


dip [sg], 8 Oct 2005, 17:58 reply
hm.. 1 matrix itu cuma buat example sih kubilang, kan matrix nya bisa dapet dr search orang nya situs ini??
btw, td aku search orang ada yg gk ketemu.. padahal jelas2 masi di ntu..


afna [sg], 9 Oct 2005, 20:18 reply
matric ini valid tak ? 031455B03

pindut [sg], 11 Oct 2005, 10:02 reply
Kalo berdasarkan rumusnya sih harusnya hurufnya A bukan B...

yuku [sg], 18 Oct 2005, 13:41 reply
sila dicoba search Andreas Lee Astuti

pindut [sg], 19 Oct 2005, 3:03 reply
wah, sebenarnya bukan dari saya itu kesalahannya ditemukan. Saya mendengar dari sumber lain hohohoho

pindut [sg], 19 Oct 2005, 11:59 reply
Frankly speaking, i think the number is just used to differentiate other matrix number that might have the similar number due to reoccurence, hence it is good to add one more alphabetic digit in the card.It is good to prevent before a mixed up occurs... However the theory is well done...

Smart [sg], 21 Oct 2005, 13:56 reply
o
My student id is 2003080106...
Oops, I forgot this was only for NTU students :-P


William Poetra Yoga Hadisoesen [cn], 22 Oct 2005, 11:28 reply
Wah si cuwil (WPYH) buka situsnya yuku juga ^^

Imam [sg], 22 Oct 2005, 12:50 reply
sugoi

nyo [sg], 22 Oct 2005, 12:58 reply
wow..ur website is awesome!!

emmy [sg], 11 Dec 2005, 17:10 reply
untuk h mod 11 nya bisa dimengerti, dpt nilai pengali a & b nya gmn? masa dicoba satu2 =p

agus [id], 18 Mar 2006, 12:08 reply
Errr... kalo rumusnya di pake buat matirc saya juga ga valid deh... cuman kalo terakhir ditambah 11 (bukan 10) - atau ga ditambah apa2 juga bisa :p kan mod 11. sama kaya kasus si pindut >.< mungkin rumusnya salah?

Cute Girl ^^ [sg], 28 Mar 2006, 8:11 reply
how bout finding the secret behind S'pore FIN number next? ha6...

sylv [id], 19 Jul 2006, 18:00 reply
I dnt undrestand...emg mksdnya di nomor siswa NTU i2ada apanya c?

Sasha [no], 30 Jul 2008, 9:54 reply
lha? napa kaga tanya langsung aja ke NTU seh maksudnya apaan? klo tanya langsung bisa kelar cepet kalee... gue gie mumet baca rumus2 banyak2 malah tambah mumet nehh... =( lagian napa kaga ada "I" coba??

toerino82 [sg], 18 Sep 2008, 11:40 reply