Archive for September, 2008

Random Variables

Definition of Random Variable

When numbers are associated with the outcome of a chance experiment, the result is said to be a random variable.  Thus a random variable is a function with simple space S = {s1, s2,…,sN} as the domain, and a set of real numbers X = {X(S1), X(S2),…,X(SN)} as the range.

Some possible random variables we might define are the following :

1.   The number of successes.  The random variable X = number of successes is the quantity k described by the binomial distribution, B5(k,p)

2.   The trial on which the kth success occurs. The random variable X = trial for the kth success is the quantity n described by the Pascal distribution, Pk(n,p), except that we must assign the value to X in the event that no kth success occurs.

3.   The number of failures subtracted from the number of successes. This distribution we have not investigated, but it is easily treated.

4.   Binary numbers.  Another possible random variable is X = numerical value of the outcome considering A as 1 and as 0 and interpreting the number in base 2.

 

X and x ?

We must distinguish between X(s), the random variable, and x, an independent, continuous mathematical variable ranging over the real line.  For example, we set x = 0 and proceed as follows.  We perform the experiment of 5 binomial trials.  An outcome occurs.  That outcome has 0, 1, 2, 3, 4, or 5 successes.  The corresponding value of X(s) is the number of successes, a random variable.  If X(s) = 0, then the event {X(s) = x} occurred since x was set to 0.  If 1, 2, 3, 4, or 5 successes occurred, then the event X(s) = x did not occur.  For x = 1.3, the event {X = x} never occurs.

 

Benefit of introducing random variables

1.   Numbers come up naturally in most practical and many theoretical problems.  Usually we’re interested in some sort of numerical information.

2.   Random variables make all experiments alike.  The concept introduces a common basis for describing random experiments.

3.   Random variables allow us some distance from the chance experiment. In many situation the random variable can be easily identified and measured, whereas the chance experiment may be quite abstract and difficult to define.

I’m getting dizzy with this kind of lesson…what a difficult statistics…! But please understand this…

Taken from the Modelling Random System by J.R. Cogdell

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First Ied Fitri in Taiwan (miss my Indonesia…)

Today, after the two days of typhoon, we celebrate the Ied Fitri in Taiwan. It’s one day faster than in Indonesia. Not so special. So quite and cold. Maybe the only thing that makes me happy is meeting people in Taipei Grand Mosque. Mostly are Indonesian. I meet many women workers. Some of them look so happy, but inside they miss their parents, brother, sister, son, or daughter in Indonesia. I can understand their feeling. Since I feel the same like them. I miss my mom a lot. I want to cry, but I arrest my tears from coming out. That’s why I go to my dorm soon.

Along the way to the dorm, I remember all the people that I love most in Indonesia. Every single siluets of them makes me want to cry. I believe that all of the people are happy because of the Ied Fitri. But, it’s totally different for me. There’s no enliven, there’s no Allahu Akbar said in the takbiran night.

In the early morning, i send the email to my friends, saying that I’ve celebrated the Ied Fitri. Then the most surprising thing after I get in my dorm and see the inbox of my email, I see that there’s a reply from Pak Katili. hehehe… he’s always nice, always keeping my spirit high. Thanks for all the supports. And the most important thing is calling my parents and brother in Depok. The city that I love most.

For every people in the world, please accept my forgiveness. For all the things I’ve done wrong, for all the words I’ve made mistakes, for all the behavior that I’ve hurted. Please forgive me… The most important thing is not the place where we celebrate the Ied Fitri, but the holiness of Allah’s mercy after doing the religious services. Keep my spirit high…

Allahu Akbar, Allahu Akbar, Allahu Akbar …

La illa ha illallah huwallah hu akbar…

Allahu akbar walillah hilham…

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I prefer calling “Pak Katili” to “Prof. Katili”

He’s one of the most influencing person in my life. Not only because of his brilliant mind but also his kindness to his students. He has got the greatest part in his academic journey. He even found a new formula in finite element method for the new type of element for plate. What a proud to know him as my lecturer! DKMQ (Discrete Kirchhoff Mindlin Quadrilateral) and DKMT (Discrete Kirchoff Mindlin Triangular)…that were the type of the element. According to him, this type of element passes the Patch Test and awfully showing a good performance. I’ve ever seen the formula and do some assignments by using this type of element. It’s trully confusing. But, it’s interesting…Since I just count not derive the formulation. I can’t imagine how did he do that.

Beside of his brilliant mind, he is so nice and kind. But some of my friends are affraid to be with him. He really appreciates us as his students. Sometimes he was so strict, but I appreciate that since that’s his principle. And his principle is good, there’s no need to be indifferent. I like to be taught by him. A very different way of teaching. So don’t get surprised when you face many problems to be done without his detail explanation before. The more you try to solve the problem, the more question will come up to you. Interesting, right…? Eventhough he is a Professor but I never call him by “Prof. Katili”. I just call him “Pak Katili”. I don’t know why, but some friends of mine who has a good impression on him, always say that he looks like our father. Yes..that’s what I mean. The more you know him, you’ll feel that he treats you as his son or daughter.

For Pak Katili : you are one of the best teacher ever… hehehe…

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Graduation Day (August 29th, 2008)

Today, I have no feelings about this graduation. All of the processions are just formality. I feel so tired today actually. After fulfilling the whole week by going round and round from Depkumham to Deplu, and today is Friday so I have to do the weekly routine tasks.  The most important moment was yesterday. Even though, it’s just a rehearsal but it’s full of meaning. Meet my friends and share some beautiful moments. According to my friends (yeni, firna, and mbak yanti), the most important thing is taking a picture of us. Oh my God, I can’t believe that many of them are truly “NARSIS ABIZZZ…”

I’m just going to remember the rehearsal day. Pipit come to Balairung just to record all the procession, but she is also take many pictures of us. And she is also having a picture of herself gubrakssss… All of them really love to take some picture, but I’m not really, since I don’t have any camera hehehe… Pak Dedy also come just to support us to pay the bill at Pizza Hut hihihi… He is so kind and nice, but he is also mean to me especially connecting to… (No need to be published).

All the girls look so pretty especially firna, yeni and mbak yanti. They spend some money to the saloon, but they’re not disappointing. “You are looking good girls!” Look soft and enchanted.

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The Battle Starts Now

After many hard days at the campus just to get my original diploma and academic transcript, the real battle is starting now. I have to count on myself to finish all the requirements needed before I get to Taiwan. At the campus, I can ask Mr. Katili to help me deal with the system. Ugh… I can’t stand with the system. Take so many procedures to be passed, and positively they take much time to finish.

The system at the Indonesian government is really confusing. That’s why some friends of mine prefer to let other people to take the documents care. I insist to take care of them by myself, as I don’t have enough money hihihi… Beside if I know the process, I can see the government’s productivity. What a words! Hehehe…

For some persons, dealing with systems is confusing. The systems make not to be effective sometimes. We get a very long way just to get something. It’s different with queuing.

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He’s Out Just Because of Me

From the frst time I come up to the school environment, I don’t feel so safe. I just feel curious to be there. Since I didn’t attend the kindergarten school, so I started my school time in the Elementary school. As an elementary student, I was so worry that my mother would not be with me. So she would not accompany me to do many things that I couldn’t do by myself.

But, I had some very wonderful teachers. They treat me like their own son/daughter. They keep me warm. Eventhough, still my mother was waitting outside. I have a very memorable story about my elementary teacher. His name is Pak Namin. He is an Islamic religion teacher. Actually he is so kind, but when he came up to the class I was crying as hard as I can. Do you know why? Because he was wearing glasses. What’s wrong with glasses! That’s the story begins. I was so affraid of the blind people. People who are blind usually wears dark glasses. And in my age, I couldn’t differ the dark glasses and other glasses. I just thought that the people who is wearing glasses is blind.

I was a weird people at that time, some friends of mine always laughed everytime I started to cry when Pak Namin entered the classroom. The solution was my mother attending the class just to make me calm. So funny 🙂 My mother always gave me an understanding, that Pak Namin was not blind. “If he is blind, how could he teach you and your friends”, my mom said. At that time she told about that I think that I can understand. But when the Pak Namin’s class began, I forgot all of my mom’s sayings. I cried again and again, and my mom attended this class again…

All of the teachers and also the headmaster tried to find the solution for my problem. They decide to change the Islamic religion teacher with Bu Yayah. Then the tragedy stopped. But, after I grow up, I always thinking why did Pak Namin out from the school. It should be me who is out from the school. Just because of 1 person, the lovely teacher is ready to be transferred to another school. Oh my goodness…What kind of a student I was..!

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She’s in, I’m out

Senangnya mendengar risma diterima kuliah di Sistem Informasi UI. Mantap dah pokoknya, tapi bertepatan dengan itu aku keluar dari kampus. Alhamdulillah dah lulus, setelah berjibaku melawan hari2 melelahkan.

Yang lebih mantap lagi adalah, dulu risma jurusan Teknik Sipil trus dengan keinginannya yang super kuat dan meyakinkan, akhirnya masuklah dia ke Sistem Informasi UI. Hebatnya semua dihadapinya seperti sebuah kejutan. Ini nih hebatnya orang optimis, melihat sebuah kesulitan didepan sebagai sebuah kejutan, bahkan sebuah tantangan untuk dibuktikan kebenarannya.

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