大世界 3.3
* A stupid man’s report of what a clever man says is never accurate, because he unconsciously translates what he hears into something that he can understand.
o Book One, Part II, Chapter XI, Socrates, p. 83
— Bertrand Russell
— Me@2010.11.05
2011.03.03 Sunday ACHK
My self-summary
I am a physicist by nature, an educator by miracle, and a writer by destiny. — Me@2010.09.21
What I’m doing with my life
Transforming myself by transforming other people’s lives. — Me@2010.09.21
I’m really good at
… being amazing. — Me@2010.09.21
The first things people usually notice about me
I am always with my Palm computer. — Me@2010.09.21
Favorite books, movies, shows, music, and food
Contact（超時空接觸）
Life is Beautiful（一個快樂的傳說）
Back to the Future（回到未來）
— Me@2000
I spend a lot of time thinking about
Physics and Love
Dear Mrs. Chown,
Ignore your son’s attempts to teach you physics. Physics isn’t the most important thing. Love is.
Best wishes,
Richard Feynman
— Me@2010.09.21
The most private thing I’m willing to admit
The secret to creativity is knowing how to hide your sources.
— Albert Einstein
You should message me if
… you are curious about the world and you value joy, truth, beauty and justice more than “success”.
— Me@2010.09.21, Based on Richard Stallman
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2011.03.05 Saturday (c) ACHK
所以，如果你想驗算的話，你可以代（例如） x = 0.003217 入左右兩邊，看看左右兩邊是否數值非常近似。
LHS :
RHS :
如果左右兩邊的頭幾個對應數字都相同的話，你的方程式答案
就有很大機會正確。
用這個驗算方法，選擇 x 的數值時，有一些地方要留意。
第一， x 一定要是在 1 和 -1 之間的數字。
第二， x 千萬不要代一些公整的數字。太公整的話，例如 0 和 0.5 等，你很可能會「撞中答案」。即使左右兩邊的數字答案非常接近，你也不能確定，那是因為你的運算正確，還是只是巧合。
第三， x 不要太大。太大的話，例如 0.3217，即使你的方程式答案正確，左右兩邊的數字答案亦未必會接近。
第四， x 不要太小。太小的話，例如 0.000003217，你會校對不到右手邊方程式最後一項（）的係數（281）是否正確。
— Me@2011.03.04
2011.03.05 Saturday (c) All rights reserved by ACHK
String theory 9
U-duality is a symmetry of string theory or M-theory combining S-duality and T-duality transformations. The term is most often met in the context of the “U-duality (symmetry) group” of M-theory as defined on a particular background space (topological manifold). This is the union of all the S- and T-dualities available in that topology.
The narrow meaning of the word “U-duality” is one of those dualities that can be classified neither as an S-duality, nor as a T-duality – a transformation that exchanges a large geometry of one theory with the strong coupling of another theory, for example.
— Wikipedia on U-duality
2011.03.04 Friday ACHK
點石成金 2
石的存在目的，是被點成金；種子的存在目的，是長成大樹。
無石不會有金；無種子不會有大樹。
— Me@2011.01.31
The sole purpose of the existence of the first idea is to be rewritten.
— Based on Paul Graham
— Me@2010.09.21
2011.03.04 Friday (c) All rights reserved by ACHK
Startup 6
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In an essay I wrote a couple years ago I advised graduating seniors to work for a couple years for another company before starting their own. I’d modify that now. Work for another company if you want to, but only for a small one, and if you want to start your own startup, go ahead.
— Paul Graham
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2011.03.04 Friday ACHK
最簡單的例子是，一個人的「左腦」和「右腦」，各自都是一個完整的「人」。
對於正常人來說，左腦控制右邊身體，右腦控制左邊身體。左腦和右腦各自控制半個人。它們互相合作，令到一個人能夠過完整的生活。令我驚奇的是，那不是事實的全部。
我看過一輯 BBC（英國廣播公司）的記錄片，描述有一個小童（甲），因為左腦大部分的細胞壞死了，導致他不能有正常的思考，不能過正常的生活。他的家人決定讓醫生移除他左腦的大部分。手術之後，他的右半身失去了左腦的指示，暫時不能正常運作。但是，經過一連串的訓練和治療，他的右腦漸漸地接管了他整個身體的運作，包括了原本由左腦控制的右半身。還有，一般人由左腦負責語言，而甲卻失掉了左腦，本應自此口齒不清。但是，透過不斷學習，他的右腦漸漸地掌握了語言。
甲失掉左腦，結果最後卻可以過正常完整的生活。他的右腦有那麼大的可塑性，主要原因是他還是小童。小童腦部的彈性還是很大。
而我想帶出的是，根本即使是單獨一個左腦，或者是一個右腦，都有潛能掌管一個人的整個身體，負責一個人的整個生活。從這個角度看，左腦右腦各自都是一個完整的「人」。而正常人都有左腦右腦，即是正常人都至少同時有兩個「自我」：左腦和右腦。
我們可以假想一百年後，科技發達。如果你願意的話，你可以要醫生把你的右腦移植去一個機械身體，而左腦則留在原本的身體。那樣，你就由一個人變成了兩個人。
— Me@2011.03.03
2011.03.03 Thursday (c) All rights reserved by ACHK
Left brain functions
sequential
analytical
verbal
logical
linear algorithmic processing
mathematics: perception of counting/measurement
present and past
language: grammar/words, literal
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— Wikipedia on Lateralization of brain function
— Me@2008.01.13
— Me@2022-01-23
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2011.03.03 Thursday ACHK
大世界 3.2
Our hypothetical Blub programmer wouldn’t use either [Cobol or assembly]. Of course he wouldn’t program in machine language. That’s what compilers are for. And as for Cobol, he doesn’t know how anyone can get anything done with it. It doesn’t even have x (Blub feature of your choice).
As long as our hypothetical Blub programmer is looking down the power continuum, he knows he’s looking down. Languages less powerful than Blub are obviously less powerful, because they’re missing some feature he’s used to. But when our hypothetical Blub programmer looks in the other direction, up the power continuum, he doesn’t realize he’s looking up. What he sees are merely weird languages. He probably considers them about equivalent in power to Blub, but with all this other hairy stuff thrown in as well. Blub is good enough for him, because he thinks in Blub.
When we switch to the point of view of a programmer using any of the languages higher up the power continuum, however, we find that he in turn looks down upon Blub. How can you get anything done in Blub? It doesn’t even have y.
By induction, the only programmers in a position to see all the differences in power between the various languages are those who understand the most powerful one. (This is probably what Eric Raymond meant about Lisp making you a better programmer.) You can’t trust the opinions of the others, because of the Blub paradox: they’re satisfied with whatever language they happen to use, because it dictates the way they think about programs.
— Paul Graham
2011.03.02 Wednesday ACHK
You can only rank people with lower rank than you have;
you cannot rank people with higher rank than you have.
— Me@2011.03.02
2011.03.02 Wednesday (c) All rights reserved by ACHK
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… games is a good way to socialize …
– Halcyon Days (book)
– James Hague
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2011.03.02 Wednesday ACHK
二項式定理有一個驗算方法。例如，題目要你把 展開（expand）至
為止。而你運算到的答案是
。你怎樣可以知道，自己有沒有運算錯誤呢？
首先，你要知道，這種題目的目的，是要做近似值，以簡化運算。如果把 的所有項也寫出來的話，你總共要寫 24 項。
如果你只想寫（次方由小至大的）頭幾項，而又要近似值足夠準確的話，x 一定要是在 1 和 -1 之間的一個很小的數值，因為 x 的數值越小， x 越大次方的數值就越可以忽略。例如，x 是百份之一的話， x 二次方就是萬分之一。而 x 三次方就是百萬分之一。
— Me@2011.03.02
2011.03.02 Wednesday (c) All rights reserved by ACHK
Physics Town 