Apr 17

 

没找到来源。。。

 

 

不过本文关于米国CS计算机的介绍实在是太可爱了,不得不收藏,感谢 Xi Tan

 

# 前言 #

1. 讨论一下计算机领域的牛圈和‘带头大哥’;

2. 讨论一下科研方法;

3. 讨论一下计算机领域的学术论文(会议、期刊);

# 第一章 #

计算机的大牛90%以上都在美国,所以只讲讲美国的CS。别的国家没什么太大的参考意义(英国、法国、匈牙利、日本、香 港、新加坡、大陆、加拿大),不过 还是说两句:第一句是,美国以外的地方CS和美国有差距,主要是没钱;第二句是,搞科研也讲‘近亲繁殖’,美国以外的其他地方很明显‘人手不够’。没钱的 问题看大陆就知道,高性能计算、硬件、网络。。统统没办法干。当年人家Stanford跑一个粒子加速器就几百万美金,中国哪个高校有这资金。人手问题也 很明显,像Stanford的Dan同学,以前在Cololado Boulder,后来不也被挖走了?像以前呆在加拿大一个人闷做研究的Han Jiawei老大,不也被UIUC挖走了?为什么呢。说白了还是资源。Han Jiawei 02年被UIUC从加拿大的SFU拎到UIUC,转年就成了IEEE的FELLOW。为什么。说白了就是‘近亲繁殖’。直到现在美国相当数量的大学(就不 说全部了)都非常认可同行的推荐。学校要各个同行评分,发paper也是同行review,nominate也要同行,甚至PhD的 application也相当依赖reference letter。另外呢,就是这些资源相当丰富的地方容易产‘奶牛’。当年吴健雄也才第九名考进的中央大学,可是人家一跑美国去就成了实验物理大牛,还当了 美国协会的会长。物以类聚,人以群分。你说90%的老大都在美国,你呆在印度做CS,有啥意思。不管是Science还是Engineering,还得靠 inspiration。Inspiration靠什么?显然是要以Group为研究的基本单位,像Dan Jurafsky和Jiawei Han那样的人毕竟是少数。最好不还是被几个牛棚给挖走了?这玩意真没办法,是趋势。不说废话了,来扯美国的CS。

Dec 9
       
         19世纪初,在英国中部的约克城,红、绿装分别代表女性的不同身份。其中,着红装的女人表示我已结婚。而着绿装的女人则是未婚者。后来,英国伦敦议会大厦 前经常发生马车轧人的事故,于是人们受到红绿装启发,1868年12月10日,信号灯家族的第一个成员就在伦敦议会大厦的广场上诞生了,由当时英国机械师 德·哈特设计、制造的灯柱高7m,身上挂着一盏红绿两色的提灯——煤气交通信号灯,这是城市街道的第一盏信号灯。在灯的脚下,一名手持长杆的警察随心所欲 地牵动皮带转换提灯的颜色。后来在信号灯的中心装上煤气煤罩,它的前面有两块红、绿玻璃交替遮挡。不幸的是只面世23天的煤气灯突然爆炸自灭,使一位正在 值勤的警察也因此断送了性命。从此,城市的交通信号灯被取缔了。直到1914年,在美国的克利夫兰市才率先恢复了红、绿灯,不过,这时已是“电气信号 灯”。稍后又在纽约和芝加哥等城市,相继重新出现交通信号灯。
        随着各种交通工具的发展和交通指挥的需要,第一盏名副其实的三色灯(红、黄、绿三种标志)于1918年诞生。它是三色圆形四面投影器,被安装在纽约市五号街的一座高塔上,由于它的诞生,使城市交通大为改善。
        黄色信号灯的发明者是我国的胡汝鼎,他怀着“科学救国”的抱负到美国深造,在大发明家爱迪生为董事长的美国通用电器公司任职员。一天,他站在繁华的十字路 口等待绿灯信号,当他看到红灯而正要过去时,一辆转弯的汽车呼地一声擦身而过,吓了他一身冷汗。回到宿舍,他反复琢磨,终于想到在红、绿灯中间再加一个黄 色信号灯,提醒人们注意危险。他的建议立即得到有关方面的肯定。于是红、黄、绿三色信号灯即以一个完整的指挥信号家族,遍及全世界陆、海、空交通领域了。
        中国最早的马路红、绿、灯,是于1928年出现在上海的英租界。
 
注:对车辆和人来说都是红灯停,绿灯行,黄灯是用作车辆缓冲信号(持续3s,车辆不可能立即停下来嘛)。

 

Apr 10

走出房间类的解迷游戏很多人都玩过,就是点击房间的每个角落,寻找线索走出房间。下面提供一个游戏,并有详细的解决过程,让大家体会这种游戏的思路。

Mar 28

来源:www.matrix67.com

代码分析在这里

Mar 20

Ah, homeward bound I go!
Why not go home, seeing that my field
and gardens are overgrown?
Myself have made my soul serf to my body:
why have vain regrets and mourn alone?

Fret not over bygones
and the forward journey take.
Only a short distance have I gone astray,
and I know today I am right,
if yesterday was a complete mistake.

Lightly floats and drifts the boat,
and gently flows and flaps my gown.
I inquire the road of a wayfarer,
and sulk at the dimness of the dawn.

Then when I catch sight of my old roofs,
joy will my steps quicken.
Servants will be there to bid me welcome,
and waiting at the door are the greeting children.

Gone to seed, perhaps, are my garden paths,
but there will still be
the chrysanthemums and the pine!
I shall lead the youngest boy in by the hand,
and on the table there stands a cup full of wine!

Holding the pot and cup, I give myself a drink,
happy to see in the courtyard the hanging bough.
I lean upon the southern window with an immense satisfaction,
and note that the little place is cosy enough to walk around.

The garden grows more familiar
and interesting with the daily walks.
What if no one knocks at the always closed door!
Carrying a cane I wander at peace,
and now and then look aloft to gaze at the blue above.

There the clouds idle away from their mountain recesses
without any intent or purpose,
and birds, when tired of their wandering flights,
will think of home.
Darkly then fall the shadows and, ready to come home,
I yet fondle the lonely pines and loiter around.

Ah, homeward bound I go!
Let me from now on learn to live alone!
The world and I are not made for one another,
and why go round like one looking for what he has not found?

Content shall I be with conversations with my own kin,
and there will be music and books
to while away the hours.
The farmers will come and tell me that spring is here
and there will be work to do at the western farm.

Some order covered wagons;
some row in small boats.
Sometimes we explore quiet, unknown ponds,
and sometimes we climb over steep, rugged mounds.

There the trees, happy of heart, grow marvelously green,
and spring water gushes forth with a gurgling sound.
I admire how things grow and prosper
according to their seasons,
and feel that thus, too, shall my life go its round.

Enough!
How long yet shall I this mortal shape keep?
Why not take life as it comes,
and why hustle and bustle like one on an errand bound?

Wealth and power are not my ambitions,
and unattainable is the abode of the gods!
I would go forth alone on a bright morning,
or perhaps, planting my cane,
begin to pluck the weeds and till the ground.

Or I would compose a poem beside a clear stream,
or perhaps go up to Tungkao
and make a long-drawn call on top of the hill.
So would I be content to live and die,
and without questionings of the heart,
gladly accept Heaven's will.

-- excerpted from The Importance of Living, by Lin Yutang


Mar 17

你也许看进球Top 10,音乐Top 100,电影Top 20之类的东西,有想过给数学定理排名吗?
在99年的一次数学大会上有人给出了“百大数学定理”列表,附有定理证明的时间和证明者。
http://personal.stevens.edu/~nkahl/Top100Theorems.html

其中,排名前十位的数学定理如下:
1. 根号2是无理数
2. 代数基本定理
3. 有理数集是可数集
4. 勾股定理
5. 素数定理
6. 歌德尔不完备定理
7. 二次互反律
8. 不可能尺规三等分角和倍立方体
9. 圆的面积
10. 费马小定理的欧拉推广

Mar 10

今天看到一个网站,上面有好多情书,还没有MM的可以好好学习下哦!

http://www.sleeptrip.com/300loveletters/041.html