Sunday, October 21, 2012

What is Love?

Love is commitment.

這是我最近聽到最好的解釋,特別在此紀念。 2012/10/17

若是用人都是從自己出發的利己看法來看的話,怎麼看都是deae-end。

A Clockwork Orange


P.27 
人被賦予了自由意志,可以由此來選擇善惡。只能行善或者只能作惡的人,就成了發條橘子 ── 也就是說,他的外表是有機物,具有可愛的色彩和汁液,實際上僅僅是發條玩具,由著上帝、魔鬼或無所不能的國家(他日益取代了前兩者)操縱。徹底善與徹底惡一樣沒有人性,重要的是道德選擇權。惡必須與善共存,以便道德選擇權的行使。



sandel 討論串


延續之前例子,有一個人花很久的時間排隊滿演唱會的票,有人出價10萬跟他買,他賣了。你會說,這沒有效益最大化,因為出高價的人沒有排隊排很久的人想看那場演唱會。這樣想我覺得是錯的。因為效益最大化是綜合的考量而非單一事件的陳述,你可以假設排隊的那個人家裡有個重病的女兒,他需要醫療費用,所以他女兒治癒的效果對他來說相當大,綜合考慮的結果,他決定售出他手上的票。

你會覺得怪怪的地方在於,有錢人好像付出了相對較少就得到他想要的,這樣的交換對沒錢的人好像不公平,不過這就是資本主義,用錢去衡量事務。資本主義可怕的地方是任何事物都有一個價錢,大家不能接受,因為這樣不就是富者恆富、窮者恆窮,這也沒有錯,我們身處這樣的社會,我們自己最清楚。但我們能接受嗎?我們一定都會說我們不能接受,但是換個角度想,若你成為了一個當權者、一個有錢人,你不會這樣做嗎?我想你也會的。所以我覺得這不是個人的問題,而是政策的問題,資本主義就是向錢看齊,也比較自由。我們嚐到了資本主義果實下的自由,大家都不能忘懷,較沒錢的人卻不能接受什麼都用錢解釋,這就是人本身的問題了。不過還有一個點,就是我們能夠選擇嗎?我能夠選擇自己生下來是在資本主義或是社會主義的國家嗎?我們能夠選擇自己生在有錢的家族或是沒錢的家庭嗎?我們並不能選擇,那這樣我們要怎麼辦?這個問題超難,我現在都還不能回答。

繼續闡述,我覺得效果最大化是個人經驗累積的產物,隨著我們在生活中累積經驗,我們逐漸找到屬於“我們個人的”效果最大化方式,也因為它牽涉到個人的選擇,人都會被騙,被別人騙也被自己騙,所以我們常常不能做到經濟學所謂的效益最大化選擇。經濟學試圖解釋社會的現象,我們都知道他的模型不是完美的,但是他的科學辦法讓我們能夠有一個參考的依據,不過他用的是統計學的量化辦法,統計能解釋的是母體,解釋個體的能力就沒有那麼好。這次的討論,常常牽涉到個體的選擇,有時候沒有辦法完美解釋我覺得是可以理解的。



Thursday, October 18, 2012

Beta


Beta就是在講系統性風險,大於1表示個股報酬率的波動幅度

比市場大;小於1則比市場小。



βCov(X,M)  Var(M)  




要計算某一個股的β值,首先我們先列出該股每日的收盤價(P)與加權指數(I),再算出其每日漲跌幅(見圖一)。算出個股的漲跌幅( 就是公式中的X )與加權指數的漲跌幅( 就是公式中的M, 也就是巿場 Market之意 ) 之後,代入β值的公式內即可算出。如果只從代數上的意義來看,要明瞭β值在投資學上的意義比較困難,但如果從幾何學上的觀念來看,就比較容易明白其代表的意義,以下我們用簡單的幾何圖形來解釋。

圖二是一個座標圖,橫軸代表加權指數的漲跌幅,縱軸代表某一支個股的漲跌幅,因為目前漲跌停板為7%,所以用正負7來代表。假如只有4個樣本點,那將之畫在圖上如圖所示,此時我們要畫出一條直線,使得該直線與各個樣本點的「垂直距離平方的總和」為極小,那麼這條直線的「斜率」就稱為β值。
  
如果你學過統計學的最小平方法(OLS),或者學過計量經濟學,那麼對β值就不陌生,因為在計算一般最小平方法時,所算的Y=α + βX,其中的β,就是我們現在所說的β值,兩者完全相同毫無差異。






Saturday, October 13, 2012

要用的數學


  • Linear Algebra
線性代數,可以用矩陣表示運算過程。

高斯消去法              check
高斯約旦消去法      check


  • The Calculation Difference Between Real Number And Matrix

1. AB is not equal to BA

2. AC=BC,
    if C is not equal to 0,
    A is not equal to B.

(AB)T=BTAT
A*AT=symmetric
(AB)-1=B-1A-1

Ito's Lemma

Stochastic Method

Brownian Emotion

Friday, October 12, 2012

The Pricing of Options and Corporate Liabilities

Fischer Black/ University of Chicago
Myron Scholes/ MIT

The Valuation Assumption
a) The short-term interest rate is known and is constant through time.
b) The stock price follows a random walk in continuous time with a variance rate proportional to the square of the stock price. Thus the distribution of possible stock prices at the end of any finite interval is lognormal. The variance rate of the return on the stock is constant.
c) The stock pays no dividends or other distribution.
d) The option is "European", that is, it can only be exercised at maturity.
e) There are no transaction cost in buying or selling the stock or option.
f) It is possible to borrow any fraction of the price of a security to buy it or to hold it, at the short-term interest rate.
g) There are no penalties to short selling.

幹後面的數學我看不懂...........

7 果实与种子的传播风&自动弹力

Aircraft designers have tried to build the wing as efficient to this one, but failed. Even the faintest # by the slightest therm is enough to lift this little glider with seated passenger, and so extended its flight.

#Plams #preseated #humanity and building fixed-wing gliders, and not any gliders. They created helicopters too. #Sickmore seadge. The balance between the weight of the seed and length and the width of the wing is exact and perfect. A slightest heavier seed or a shorter or narrower wing, and the whole thing will fall like a stone. A #tristar plant produces a revolving seeds with six plates. And aircraft designers have yet to copy that. Or this. Plants also use explosive. Jet propulsion. This is squirting cucumber. And this #humalien bosson. Its seeds catch upon a flood of liquid, such as pressure. The slightest touch make it explode. The force is so great, that the seeds can be shot away as much as 15 feet.

航空設計師曾嘗試設計出如這個翅果一般具有飛行效率的飛行器,但是都失敗了。若是成功設計出像這個翅果般的飛行機具,就連最輕微的熱對流都足以支撐其載有乘客的飛行,並延長其總體的飛行時間。
羽翅果實植物不僅僅製造像滑翔翼的翅果,他們也生產直升機。#$%^&。種子的重量和羽翅的長寬有著最精準的平衡,稍微重的果實或一點點短窄的翅膀都可以使翅果像石頭般的墜毀。[某種三星什麼的植物]生長出有著六片槳葉的旋轉種子,就連現在的航空器設計師都無法做出像那樣的直升機,或是這個。植物有時候也會用爆炸,像這個噴射小黃瓜。還有這個[什麼鬼花的],她的種子有膨壓,會感觸到最微弱壓力,一點點輕微的外力都可以使他射出(好糟糕)。那噴射的力量相當大,他的種子可以被傳播到15呎外的區域。
(for the record.英文再進步再改吧)

Saturday, October 6, 2012

things need to be achieved in graduate school

1. master in statistics software/ Matlab and VBA
2. get FRM
3. have one or two intern experience
4. exchange student

Wednesday, October 3, 2012

maturer mentally

What is the reasoning point of women maturer than men?
More thoughtfully?
Then follow the point of above, I don't think so.
And the statistics are usually biased or inconsistent, or even wrong modelling.
Yet, not seeing a formal essay or paper investigating about it.

Monday, October 1, 2012

Man and Wife

    Was talking with willow about her girlfriend that did she ever done anything that makes him feel "oh man, it is because of her age."
    However, he told my that, girls doing things capriciously, without planning, don't care much about the consequences, is not because of their age but their nature: exclude those women who put their goals on being rich, career successful, generally, girls' goal will on family ultimately, so they don't have the commensurate social responsibilities with men, so they can do whatever they want literally.
    Same thought. So you girls don't ever tell me again that you girls are maturer than us mentally, no, you don't because you don't really have to face the result after failure.